This bug is still present when you start kantu from the command line sometimes you open several Kantu windows together and the macros conflict. Please try to solve this problem is very serious and prevents automation.
I use firefox 69 or firefox ESR 60 with Kantu 5.1.9 Windows 7 32 bit
Latested Kantu addon for firefox have more bugs it’s unususable, i reported it with images but i not received any support.
I resume the bug when run firefox with Kantu from command line
Firefox 69 or Firefox ESR 60 With Windows 7 Italian
Sometimes when you run firefox with Kantu via command line if Firefox opened slowly the macro can not start, and remain firefox opened with Kantu windows but the macro do not start (no log saved)
Sometimes when you run firefox with Kantu via command line if Firefox opened slowly you can find multiple Kantu windows and create conflicts in this case the macro do not work and generate more error in log and freeze Kantu.
To verify these bug you can perform a batch file to run firefox and kantu multiple times and you will find sometimes Kantu stucked (the macro do not start) or multiple Kantu windows opened and the macro do not run.
I notice that when firefox loads slowly it is more frequent to notice these errors.
I did the tests using the macros saved in hard drives (xmodules)