platform wants to update my esr 45 portable to 50 (not esr)!!

hello,

today I took a backup of my firefox 50.0.2 installation, since I decided to try the esr 45.5.1 version,
why I installed in the original folder which firefox 50.0.2 was, using the appropriate paf file,
then I opened the platform to check if everything was ok and to my surprise saw that
it wanted to update my esr installation to 50.0.2!
appinfo.ini file is correctly indicating that this folder is containing an esr version,
but the platform doesn't recognize it and wants to install the latest release,

any suggestions/workaround?