Hi all,
Vague recollection of having experienced the following in some other context but passed it off as a fluke or was distracted before posting. See Edit below --checking other portables was a thought which bubbled-up thru the vagueness. Seeing if portables would run under fossapup would have been one of the first things I would have explored after deploying fossapup.
Using Iron-portable as an example, Mike Walsh structures the portables he publishes so that within a folder named Iron-portable there's another folder named, for example, iron64. Iron64 contains all the binaries, libs and other essential files, including a bash-script (wrapper) named iron-pup. Iron-pup sets up the conditions needed to run iron under Puppies [such as no-sandbox] then calls the actual binary named 'chromium'. Within the iron-portable folder but exterior to the iron64 folder is a bash-script named LAUNCH which calls the iron-pup wrapper. The system is designed to enable starting the application by file-browsing to and clicking the LAUNCH bash-script, saving you from having to browse into the iron64 folder and find iron-pup among its many files. You could by-pass the LAUNCH script and start the application by clicking the iron-pup wrapper. This system enables portables to be added to the Start-Menu by including a bash-script 'on the path' calling either iron-pup or LAUNCHER and identifying the bash-script on the path as the executable in /usr/share/applications/....desktop's Exec= argument.
Under fossapup, neither clicking nor double-clicking either iron-pup or LAUNCH does anything. On the other hand, Right-Clicking either and selection "run in terminal" starts the application. Both iron-pup and LAUNCH were script created in puppies other than fossa. Hypothesizing that might have had some effect, I recreated the scripts in fossapup. Those also did nothing. So, there does not appear to be anything wrong with either the portable-application or bash-scripts.
Edit: Just checked Mike Walsh's other portables: google-chrome, opera, vivaldi. Same problem. On the other hand, Brave-portable, lossless-cut, and all mozilla-based and palemoon portables do start by clicking their respective 'wrappers'. Brave's wrapper configures it to run as spot; but lossless-cut's doesn't.
So, it doesn't appear to be a generic 'bash' problem leaving me without any clue as to what's going wrong.