Interpolation time not working

Hello! I got inspired by gneiss name's video on using block displays and cloning to having a temporary structure, and have been working on the concept for a player/tag dependent version of this using different dimensions per player/tag to store the builds in.
It works in theory, but one of my block display interpolations fully skips the animation and just jumps to the finished result. The command seems to work fine when run manually but when run via the datapack it acts up.
Does anyone have an idea why this might be the case/how I might be able to fix it?
(I can send the command or find a way to attach the whole world file if anyone is interested)