Yea, I've been thinking through what they saw from their end and reckon you're probably right. It's not the liquid aspect that is getting flagged it's the swap service, be it boltz or side swap that is probably the transaction that looks like a mix before it gets put onto Tron. Perhaps that Tron address is their own hot wallet but maybe also unique addresses for each transaction which would look mixish? I hope maybe Aqua Wallet or Samson see this note and be able to shine a bit of light on it.

Like you I've never used Tron so unsure about that part.

Personally I'm a bit wary of veering too far away from BTC onchain but fees will, I believe, get really out of control at some point soon so seeing what those who are innovating is worth looking at. I did find Liquid to have a good use case as a store of sats that I could access and use for rebalancing my lightning node when needed without having the high on chain fees make it uneconomic.