Let's ignore button triggers (doubt they are issue), your builtin animation patterns won't start when you hit play button? (Interesting)
(well even if freeze sound/physics is on, animation "should" still play)
Did you removed all plugins/make copy of scene with no plugins (and load it)?
Idk how much and what stuff you have in scene, how big it is, what did you animate,
what triggers, animation step triggers, person/atom/scene plugins loaded, etc...
maybe you have FloatParamRandomizer somewhere that is set to current time 0, idk...
Did you try chopping it down?
Just delete atom by atom all the way down to animation pattern until you find the culprit.
Basically go barebone while " playing" animation, save as new scene, load, then play it....
If you can't figure it out, feel free to share, ill gladly take a look.
Btw what vam version?