ver. 2.1.2 + Windows 10 pro: bad change bpm

good morning to all of you
I hope to be clearly seen and consoiderato my bad English.
I should point out that I use Audacity for over two years with considerable satisfaction.
but with this latest version feedback often many anomalies.
among which:
I want to mix two songs with different bpm, one of the two songs I select all and change the speed without changing the pitch, of course …
but, with this latest version, it often happens that the percussion beats are “disturbed” by a repetition of the same micro causing an annoying “echo” effect.
I repeat: with older versions this did not occur.
having Windows 10 PRO, I can reinstall an old certainly more stable version of 2.1.2 ?
thank you in advance

Which effect are you using? Change Tempo?
For higher quality tempo changing, use the “Sliding Time Scale / Pitch Shift” effect.

I use change time (not change intonation)
see picture attached
is the same function that you suggest? (“Sliding Time Scale / Pitch Shift”)

thank you

That is the “Change Tempo” effect. (the blue text is a link).
The Change Tempo effect is quick, but sometimes causes an echoey effect. This is a limitation of the Change Tempo effect and it has always had this problem, though it is not always noticeable.

The “Sliding Time Scale / Pitch Shift” effect (blue text is a link) is a newer and more advanced effect and takes longer to processes but generally produces better sound quality and does not cause echoes.

Thank you
I’ll try today