Report an issue - about cannot AllowMultipleInstances (with solving method provided)

Good afternoon,

(1) Background:
I have three portable Firefoxes working together.
Every month, I update the portable Firefoxes by deleted the old folders named "App"
and the old exe files named "FirefoxPortable.exe" , then download their new version
to replace them.

(2) Issue:
This time, the Firefoxes cannot MultipleInstances.
The "second opened Firefox" cannot launch itself.
When I open the second Firefox,
It just opens a "new Firefox windows" of the "first Firefox" instead.

(3) My solving method:
After replaced the new "FirefoxPortable.exe" with the old "FirefoxPortable.exe",
the problem solved.
When I replace the old "FirefoxPortable.exe" with the new "FirefoxPortable.exe",
the problem occur again.
At last, I decide to use the old version of "FirefoxPortable.exe" instead of the new version.
Because it fully supports the "AllowMultipleInstances=true".

(4) The version of the two "FirefoxPortable.exe" are:
The old one: "FirefoxPortable.exe" version 2.2.2.1
The new one: "FirefoxPortable.exe" version 2.3.0.0

As the above,

Thank you.