Be careful of PDF's with built in broken fields though, in which case I just add a text field on top if it's easier.
There should be nothing "wrong" I can do which makes text disappear which can't be undone, or where the click-and-drag targets are as tiny as can be.
The program is buggy. Apple releases bad software sometimes. That is simply all there is to it.
You said "mouse", is it a gaming mouse? Is it configured to issue a bazillion clicks if you press and hold "left" button - for a stupidly small number of ms, taking no consideration of you if you are playing a game? Does it also send "wiggler" (WASD) keyboard presses at the same time? Either of these will ruin any chance of you doing "undo", unless you also "undo" a bazillion times. This behavior will likely make a lot of other things behave in quite weird ways and be "slow" to respond. If you've got a gaming mouse doing auto-clicks, auto-kbd strokes for non-game apps, then the UI designed for humans is going to behave weirdly.
FWIW, the placeholder text can never really disappear, if you remove it all, you get the placeholder "Text" back again. You can replace it with a single space, but that also has a hit zone of more than 1px both H & V. Maybe you have found a bug. I do think there are issues with font background / foreground colour selection that might make it "invisible", but the hit zone will still be there.
I use an ancient mouse, "Microsoft Comfort Optical Mouse 1000" and an Apple Trackpad. I cannot reproduce what you describe.
What mouse are you using? What additional HID (Mouse, KBD) extensions do you have installed?
And, no. This is 100% Apple hardware and software. I am using Apple's trackpad, built into one of the most recent Apple laptops, using the latest Apple desktop OS.