I'm trying to add '重复性压迫损伤' to the dictionary, with pinyin as 'chong2fu4xing4​ ya1po4​ sun3shang1', but the page keeps saying that this is not valid pinyin. What am I doing wrong?

I typed a space by accident at the beginning once leading to this exact error.

I don't know this vocabulary but according to MDBG it should rather be chong2fu4 xing4 ya1po4 sun3shang1, as those seem to be the words.

I suppose that chongfuxingxapo is not a single word and as words are usually not that long the Skritter parsing algorithm detects that, thus the error.

BR,
Alex

For some reason, you have two zero-width space (Unicode 200B) characters in that pinyin. I do not know how that happened, but that is what was messing it up. I have created the word now.