Problem with switching sets and stages

Hello, I have a problem with your software. I’m on 1.3.2 app version on a Mac running 10.13 High Sierra. My computer is clean and has enough free disk space, its a MacBook Pro (Retina, 13-inch, Early 2015) with 16GB of RAM.

The software used to work OK on this machine, but since some time changing sets and stages within a set takes a long time and the app, as shown on a screenshot below, is not responsive. It was taken while switching to a second stage in this particular set.

Whats more, is that it does not happen with all presets, but with some. The size of samples and amount of settings put into particular presets seems to not matter. Some switch fast and some do not.

Since today, I had an older version of the app (1.2.something), and this situation did not change after updating to 1.3.2.

As I said before, this computer used to run thing smoothly and without any delays. Can you advise me, what can I check to solve this problem?

Regards, Jacek