You may find at the moment with the world situation that people are returning to the Bitcoin forum (such as myself) or, they may have simply lost track of certain things such as their password for this forum and have needed to change their passwords, or reactivate their accounts.
It is normal if one reactivate their accounts after more than 6 months. Many people tend to abandon their accounts (not only account on the forum, but also account on exchange) when market is bearish for months; and reactivate their accounts when market turns to bullish. On the other hand, it is very abnormal if one user reactivate after months and instantly want to run a company, want to trade with the others. The same goes for passwords changed or reset.
I do not consider the case of changing the password or recently waking up as suspicious activity from profile account (like your account). However, in trading and lending they avoid your account because of potential fraud problems but if you can verify the old BTC address then avoid these accusations.
Without trading, reactivate account does not harm the others but sometimes, the forum has seen some massive accounts woke up and spammed.