RAD Studio Rio - Debugger keeps hanging.

I have ported my project to Rio and have finally got it compiling and running to MacOS-64 bit. However I am finding a few issues when running in debug (Mac 64 bit only). When the program halts at a break-point I often get strange results interrogating string variable values and after a few seconds I get a hang (interrogating any variable value). This seems to happen with both tool tip and watch list. After a time-out period I get the following

Has this happened to anyone else and has anyone got any suggestions as to what might be causing it? Any help greatly appreciated.

Kind Regards

Rick