A Stack Exchange staff member edited your user profile's "about me" section on November 13, 2019 at 20:58:09 UTC. (As a moderator on the network, I can see this information in a history log.)
As goldPseudo pointed out, when editing a user profile, one can choose whether to save the changes only to the current site/community, or whether to copy the changes to all sites/communities to which that account is linked. The editor must have chosen the latter option. (Note that only you and moderators, including staff, have the ability to edit your profile.)
I cannot see any details of why staff would have changed your profile (such actions are typically reserved for extreme cases), but you should have gotten a message via the site and/or via your associated email address containing an explanation. These messages have to be sent manually, however, and that extra step isn't always taken. (Although I feel strongly that it should be.)
I can, however, guess at what might have caused them to edit your profile. Your network profile (which is not synced with the per-site profiles) presumably still has your original "about me" contents, which includes some commentary on pronouns:
Pronoun: Peilonrayz
None of: They, he, she, and definitely not itReflexive: Peilonrayzelf
Possessive: Peilonrayz'
Other: Peilonrayz
As you well know, this is a hot-button issue on Stack Exchange sites lately, and presumably an employee felt that your specification of pronouns violated the new policy. Given that the pronouns were all derived from your chosen nom de plume, it was most likely interpreted it as an attempt of performative protest against the policy, akin to requesting that other users refer to you as "Your Highness".
As a moderator, I personally wouldn't have touched your profile's contents, but I can understand how a staff member could have gotten the impression that they didit was trolling behavior and removed it out of respect for other users' identities.
If you want to argue against the interpretation of the policy and/or plead for your profile's reinstatement, you can contact the team. However, I would suggest just not adding sort of thing back to your profile going forward. It serves no real purpose. If it was indeed an attempt to protest, consider doing so in a more appropriate forum, like a relevant discussion here on Meta Stack Exchange.