the situation is stable since upgrade to 81.10 version and following these TAC instructions:
Please clear the cache files related to the certificate and make sure that the following steps are performed:
1. The hashed-name certificates found on relevant SMB appliances via this Expert Mode command:
find / -name *.crt
2. All hashed-name certificates deleted via Expert Mode command "rm":
Example:
rm /pfrm2.0/config1/f08dfji3hf9du3.crt
Once Above procedure is done, please try to reinitialize internal certificates on SMB appliance and after this try to connect via Remote Access VPN.