EXP39 BLF error

[jraposinho]

Hi,

I have installed a Yealink T38G with 2 EXP39
I have configured Extensions Numbers with BLF in both EXP39 but the BLF light only works from time to time.
For example:
When I plug the phone, wheter it's with POE or with the power source, all the BLF's light up for a few seconds and then only some of them works. Sudenly, some lights go off and others go up.

Here is a video I make to show what's happening:

https://www.dropbox.com/s/am84i540sqsjuy...5.mp4?dl=0

How Can i Solve this ?
Is there any incompatibility issue ?
It's happening in several other clients.

I use Yeastar MyPBX U100 and U200.

Best regards,

João Raposinho