I don't think I really have much of a choice other than to close this.
I'm not sure if things have changed in recent iOS versions but I'm only able to reproduce the context menu popping over the reactions if I do particularly weird things, namely doing a long tap and hold until the "Like" text is selected, and then adjusting the selection.
As noted, if it does pop up, you can hit "Copy" to get rid of it but it doesn't seem easy to get it to pop up now. For the most part it seems to work fine.
Let us know if it is still problematic, particularly on iOS 15 and we'll take another look.