Well, let me explain the remaining freeze issues I have encountered:
(1) STUCK AT REGEX EXTRACTION
I'm working with two different and separate Firefox sessions (profiles), each one running its own set of macros.
The first one does its own job and then it writes a text file with some important data that will be picked up lately by the second session.
In the meanwhile, the second Firefox session does its own job and at the end of the process it looks for the above mentioned text file and if found it will be opened (displayed in the browser) and scanned with a SEARCH SOURCE=REGEXP command to extract some strings that will be saved in another text log file.
Well... with iMacros prior to version 8.8.5 if the second Firefox session completed all the tasks before the first one, it simply didn't found the text file, the browser showed the "not found" page and the macro continued to search for a specific string (specified by the RegEx command) for as long as specified in !TIMEOUT_STEP.
When the first session of Firefox completed the job, the text file became available for the second one that could have been restarted exactly where it was on-hold by simply clicking the "retry" button into the "not found" page.
So, the text file was loaded and the macro completed the few remaining steps.
In such a circumstance, with 8.8.7 version, clicking the "retry" button in the second Firefox session (when the text file from first session becomes available) simply shows that file but the macro keeps being stuck at the SEARCH SOURCE=REGEXP command for indefinite time.
(2) STUCK AT FRAME COMMAND
Another circumstance of "endless wait" for a specific tag occurs when the FRAME command is encountered after a form submission.
In example: I'm using two form-filling macro. The first one takes care of entering shipping address data, then it clicks the submit button to send this data to the server. Once data have been validated, the following page is loaded from the server and the second macro is invoked to fill-in another form nested into a frame.
In such a circumstance, iMacros just get stuck at the FRAME F=1 command and won't move any further.
Stopping iMacros and manually re-launching the second macro makes the FRAME F=1 being properly processed so that the macro could proceed with remaining steps.
Well... why that same command in the same macro is properly processed if that macro is launched manually but it leads iMacros getting stuck if it's invoked by another macro?