In the overworld the warped stems glowing veins are buggy, instead of fading in and out they flash repeatedly

This is also a Canvas itself thing. However it is because this pack has not been updated for newer versions of Canvas. Canvas recently changed the way animated textures are rendered and this causes the flashing repeatedly.

A temporary fix for this, until Team Midnight Updates the pack, is going into Canvas's settings and switching "Group Animated Sprites" to "No", after that reload resources either using [f3]+[t] in game or restarting your game