Yes, One case i know the FBI set with one of I2P devs and started discussing how I2P design and how it works (The dev himself told me that personally).
So to avoid such police, its very hard, check cryptoparty in germany, or riseup…etc how many times got into police talk whether willingly or unwillingly.
This is unavoidable situation in nowadays countries sadly, but still nothing can be confirmed as a breach to the anonymity by just sitting with the police.