Stop 3B in fsulgk.sys (windows 7 pro)

I'm experiencing an issue. One of our windows 7 64bit computers has started crashing frequently with this error (the same error, the same memory location too).

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Dump File         : 022218-32682-01.dmp
Crash Time        : 22/02/2018 10:54:14
Bug Check String  : SYSTEM_SERVICE_EXCEPTION
Bug Check Code    : 0x0000003b
Parameter 1       : 00000000`c0000005
Parameter 2       : fffff880`076e3039
Parameter 3       : fffff880`0b8724f0
Parameter 4       : 00000000`00000000
Caused By Driver  : fsulgk.sys
Caused By Address : fsulgk.sys+31039
File Description  : 
Product Name      : 
Company           : 
File Version      : 
Processor         : x64
Crash Address     : ntoskrnl.exe+a62a0
Stack Address 1   : 
Stack Address 2   : 
Stack Address 3   : 
Computer Name     : 
Full Path         : C:\windows\Minidump\022218-32682-01.dmp
Processors Count  : 4
Major Version     : 15
Minor Version     : 7601
Dump File Size    : 262.144
Dump File Time    : 22/02/2018 17:57:45
==================================================

I have cross-checked the file fsulgk.sys with other computers, that show no issues, and it seems to be the same version, that is 11.03.101.136 (463f17e).

I have temporarily removed F-secure from the affected PC, so that the user can go on working, and I will try again later to resolve the issue. Googling did not help at all.

Any idea?

Thanks

Fabio Muzzi