This is a really niche problem, as I have not already found it on the internet, I thought it worth posting.
When a user tries to void a sales document in Dynamics GP SOP Entry, the user session would hang. Lock escalation in SQL would then follow due to the blocking causing performance to be affected for other users.
Checking in SQL activity, the problem is from two different connection sids but from the same user concerned blocking each other.
Example SQL associated with those sessions is:
select count(*) from IS010001
and SOPTYPE=2 and LNITMSEQ=16384 and CMPNTSEQ=0
The issue looked to be linked to the manufacturing module dictionary being installed but the module was not fully configured. It was not being used.
Taking the manufacturing module references out of DEX.INI of the client GP folder stopped the locking.