Designer Perspective 'no-project' bug

Hello, I’m facing a strange issue on the Perspective designer, the gateway version is 8.1.11, the OS is Linux, Java version 11.0.11+9-LTS.
Basically, if I try to open a view inside a folder, the view won’t be opened, instead it shows the message “no-project”:

The same view copied in the root view’s folder is opened with no problem:

I’ve encountered this problem while trying to import a local project into a client system, so it’s quite urgent for me to solve the problem. I asked the client to upgrade to the 8.1.12, in the meantime I’m asking here if anyone has found the problem and knows what’s happening?
Thanks in advance,