3.0 - Rebeaming via "time signature properties" change doesn't take effect for this score.
https://musescore.com/dmanzana/fuga_para_tres_guitarras_opus_22
I recommended to the author that he fix the beaming with the tutorial listed in the comment. It doesn't work on this score, I don't know why. I tried to make a new test score in 3/4, added some eighths, and re-beamed them by Time Signature Properties, and it worked. But not on the posted score listed above.
OS: macOS 10.14, Arch.: x86_64, MuseScore version (64-bit): 3.0.2.20666, revision: 8ca4d2c
Comments
I figured this out; this is another "rigid properties came in from XML" problem. If the entire score be selected, and "Auto beam" clicked prior to attempting to change time-signature properties, the latter functions as expected. This is one corner of a minefield with XML import.
I should upgrade my tutorial for XML users.