Bug - Persistent deathtouch effect after transform

My opponent summoned a creature with deathtouch. I used Froggify to transform it. The purple “deathtouch” overlay was still visible on the frog.

When my opponent moved the frog, it attacked a creature with 2 hp and both died, so i can’t tell if the deathtouch effect was still active. Also, I did not see if moving the frog canceled the bug.