I should have posted this into my previous post. This is a home built in 1930 and the paint in the walls are peeling and cracking. If you touch it it falls on the floor. I do not know of any paint today that does that. Particularly on the interior. Could this be lead based paint? I know it should be tested to know for sure, but is there a visual characteristic?
Even the newest paint will do this if the surface is not properly prepared. Could be moisture or could be real old. With that amount, they will most likely meet the thresholds for lead based paint remediation by a trained and lead certified contractor.
Paint on plaster often does this.
Consider it lead. Test.