While testing collapsible sections, I noticed that it is not possible to add simple text using spo page text add to an existing collapsible section on a SharePoint page. After running the command, the collapsible section settings are reset.

It seems that a change is needed in clientsidepages.ts, but I need to examine the code more.

I assume that the same issue may be connected to the spo page control set command, but I need to investigate that as well.