Yes, shilling of their shitcoin is a huge red flag for me.
To test out the chain analysis part, I sent 10k sats to my wallet just now, from a whirlpool coinjoined 100k sat UTXO. Let's see where this goes. Will reply here with updates on the transaction.
Probably my final update on this one. 13 hours after I sent a refund address to the Telegram wallet support bot, they finally processed the refund and sent the bitcoin (10k sats) to the address I provided. They used part of the refund amount to pay for on chain transaction fees, which I had no problem with (fee was high, 30sat/vB, totaling almost 6.7k sats). What I had a problem with was almost 600 sats were sent back to the original address where I had originally sent 10k sats to the Telegram wallet. That means I only got about 2.7k sats back into my external wallet. Yet, in the confirmation message they sent out in the Telegram wallet, they never mentioned withholding / sending back almost 600 sats into the original telegram wallet deposit address.
Once again, I wrote to their wallet support bot asking about the reason for withholding almost 600 sats. I asked about the discrepancy between their refund confirmation message and the actual refund amount as indicated by the on chain transaction.
Also, I tried clicking deposit in the wallet again and got the following message:
🛑 This operation is forbidden. Please, contact our support team @wallet_supportbot
Seems like they not only flagged my transaction, but also flagged my account and won't let me deposit anymore bitcoin. Of course, I also asked about why I wasn't able to deposit anymore.
I got the following response almost 5hrs ago and have not receive any update since:
Hello,
Let us check information, please wait.
Everything about this wallet just seem off for me. As if no lightning support, using on chain only isn't bad enough, they had to kick it up a notch to do legacy address only with no segwit support.
The act of sending almost 600 sats back to themselves and not telling me about it seems strange. Was that a fee for processing the refund? If so, why did they not mention it up front, but instead, tell me that they refunded a larger amount than the actual amount? Was it a dust amount that they keep for chain analysis? Or was it just a mistake, a human error?
Then disabling my wallet from further deposits is just a d*ck move. Censorship at its finest. If you send anonymous coins into this wallet, expect your whole wallet to get banned.
All in all, I rather Telegram not add bitcoin support to their wallet. By adding bitcoin support the way they did seem like they were trying to give a bad name for bitcoin. Imagine a newcomer trying to use bitcoin for the first time; and Telegram's wallet was their first experience with bitcoin. The new comer would think that what other shitcoiners had been telling them were all true; that bitcoin is slow, cumbersome, and expensive to use. Where, in fact, it is only Telegram's bitcoin wallet that is slow, cumbersome, and expensive to use.
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I am thinking ... isn't it possible to tell services beforehand from which UTXO you will fund your wallet so they can do their chainanalysis before you fund your wallet?
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So my transaction got 2 confirmations just now, and I got the following message from the wallet bot
🔎 Deposit transaction for 0.0001 BTC ~2.93 USD is being verified. Wait for the verification results. Please contact @wallet_supportbot for the details.
As of now, my wallet shows the following balance, with the 10k sats showing on hold. I guess it’s going through chain analysis as we speak lol
💰 My Wallet
Bitcoin: 0.0001 BTC ≈ 2.93 USD Hold: 0.0001 BTC ≈ 2.93 USD Available: 0 BTC
Toncoin: 0 TON
USDT: 0 USDT
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police is on the way to your location
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Hey thanks for helping out.
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No need to thank me. I'm genuinely interested to see what they do to whirlpooled UTXOs. On the other hand, I should be the one thanking you for writing this article and raising awareness of Telegram's shitty wallet.
Telegram got a lot of attention in the bitcoin echo chambers when they announced the support of bitcoin on their wallet. Even Matt and Marty talked about it on RHR. But it seems everyone just saw the headline, then started to rave and cheer about it without actually looking at the wallet. Whatever happened to don't trust, verify? lol
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I didn't hear any raving about it. Reporting what happened is different. IIRC they were mostly talking about telegram getting banned for free speech. But, I also didn't hear any talk about the details of the implementation. Let's not pretend RHR was recommending telegram. Recall them talking about privacy tradeoffs.
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So yea, after 10 hours of funds being “on hold”, I reached out to wallet support. This is what I got from them.
Thank you for waiting. 
Your deposit has been put on hold because our systems flagged it as a high risk incoming transaction and cryptocurrency cannot be credited to the bot's wallet.
Please provide the external BTC wallet address to which we can return the funds.
Pretty much the same response as what OP got. So coinjoined sats are high risk and not ok to be sent to Telegram bitcoin wallet, even if it’s only a small amount. Not to mention using legacy addresses and fully custodial. This wallet’s so called bitcoin support is simply horrible.
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