Hi Wayne - In a word - YES, everything from a drip to a flow! Things to check, and I am assuming here that this is a being fitted as new
1 If you have just fitted it, did you ensure you removed the old seal sometimes it hides in the block!
2 If that’s OK, did you give the block a good clean to ensure no old seal bits were left in the groove
3 As was pointed out to me, some blocks have a groove / lip on the inner / outer edges, so you have to ensure that the rubber seal does not get caught on it. I did mine mind by pushing the seal in and at the same time using a fine screwdriver gently around the edges between the seal and the block
As another note, make sure the inner seal moves against the spring and is not locked in any way. When I got mine the inner sprung seal was somehow stuck and I had to free it off by turning it. This created a few flakes of aluminium to fall off so if yours is the same be careful to clear them away
Aidan