Hi! I saw your post with John, let's see what's changed in the last 9 years... (A lot has changed with how Unity UI handles layouts as well)
Immediately seeing, the fading animation starts and then continues as the position corrects itself...
Assuming this is Unity UI...
1) Try replacing "supertext.Text" with "supertext._text", this is something that I think might have changed in the last 9 years, but I'm not completely sure if it's the issue here. ("Text" I believe used to update text WITHOUT calling Rebuild(), while "text" would, but now "_text" has this function, so the issue could be that Rebuild() is being called twice here and some layout code is getting confused)
2) Try replacing "supertext.RegularRead()" with "supertext.Rebuild(true)", which I think should have the same effect, guaranteeing STM will both rebuild and read at the same time.
3) Try adding supertext.rt.ForceUpdateRectTransforms() after the "RegularRead()" line is called. (Assuming this is on Unity UI) That might force the layout to rebuild if it's a layout issue. You can also try "LayoutRebuilder.ForceRebuildLayoutImmediate()".
4) I'm also guessing at this but... does your STM object have a ContentSizeFitter on it? I've been running into some problems with nested layouts and contentsizefitter in just the last few days actually and wrote myself a rudimentary script to make sure the effects of ContentSizeFitter happen frame 1 with STM, rather than waiting for the layout update. (It just forwards information to a LayoutElement component) So I could try sending over a cleaned up version of the script with this, but with any luck it's one of the first 3 issues.
These are my initial guesses! There's nothing in that code that should be effecting text position besides those 3 things there, so there's a chance it's how AC works now... I can take some guesses at how *that* might work, but I don't use it myself! (I could ask the dev, but I'll try guessing first...)
5) What is the parent object of your STM object? Is it also moving when the text moves? What is making it move? (Thinking maybe AC is trying to use the position of the hidden text object to decide where STM should go, but not sure how it would play initially then decide to move after a few frames...)
Let me know if any of these help!
