I have not experienced or heard of that problem, however in ordinary
industrial hydraulics, I've found that smearing STP on a piston rod
will cut the cyclic operating seal friction in half for several minutes
- even if it is only smeared on the low pressure side of things.

Another possible factor is the surface finish on the O-ring groove and
the groove faces. Too smooth and this might happen.

I'm sure it is not approved, but maybe just assembling the strut with
STP as a prelubricant might help. The "ancient" type rubber is
probably neoprene - which is widely used in industrial applications
today. I doubt the O-ring compound is at fault here.