Acrobat Reader and signature with a certificate. Acrobat Reader French version

Using Acrobat Reader French version 2020.012.20048, I cannot sign with a certificate : at the time of signing drawing a zone with the mouse the zone is disappearing.

It had been working for years with previous version of Acrobat Reader (FR).

I desinstalled and I reinstalled without any improvement.

WIN FR 10 1909 Lenovo X1 i7 16 Go

It does work on another PC i7 16 Go Win 10 FR 2004 with an English version of Acrobat Reader version 2020.012.20048.