PB0 acts really strange after attachInterrupt

[imayoda]

Hi there guys :) Tonight I've encountered a strange behavior. PB0 manipulation works OK in setup, but after one INT0 interrupt (in which I equal an unsigned long variable to millis() ) the PB0 low->high manipulation results in a barely 1 volt square wave (got with oscilloscope), correct in duty cycle but very weak in voltage. My circuit is a 1 signal to 4 multiplier with direct calculation of the high and low duty cycle period from the signal sender, and behaves very regularly if I "manually" do the PB0-2-3-4 switching with digitalWrite but before the attachInterrupt.. I think it's somewhat related (I'm not a pro) with https://github.com/MCUdude/MicroCore/issues/125#issue-845317318 .. Is there something I could do? Unfortunately I'm on a run, will switch to 25/45/85 line (what a waste :crying_cat_face: ) so will leave this just as a "note".

Kind regards and thank you all