You need to set a target tempo where you want the ritard to end.

Welcome to the forum!

If I understand you correctly, you get slow speed in the whole piece (= all the measures in the entire document) - right?

Please specify the steps you’ve already taken (to solve the problem), so that we can rule out things.

I am just guessing, but I suspect that you have already

- rebooted the computer,

- tested that the problem is document specific (= it does not happen in all documents).

My first thought is that the culprit could be located in the document’s MIDI data.

You can clear selected items from the document.

In the dialog box {Clear Selected Items} I would select only Tempo Changes (to clear Tempo Changes from the entire document).

Then, click OK.

Obviously all the measures in the entire document must be selected before you go to {Clear Selected Items}.