Disclaimer: I have a ProtonMail account that I pay for. I have seen a ton of disturbing pieces about ProtonMail. Every time I've looked into them, they seem to be maliciously motivated and usually not true, or otherwise twisting of the truth. This has been a confusing thing for me because why is there a small subset of people so vehemently against them? In this case, I'm not surprised. They say quite clearly they can…
One of the first sentence on their website is "By default, we do not keep any IP logs". If as soon as police show up (Which is almost the only case that people would want their IP hidden) they give IP logs, it is clearly false advertising. The fact that only the anonymous feature is important to you will not change the fact that they do the opposite of what they advertise regarding IP logs
Is there any evidence this is what happened?
An alternate scenario is that they were not keeping logs, and were then compelled by the authorities to start keeping them on that user.