Is this possible? Could it be from the Walker SST

I recently used Walker SST on all my connections. I am very happy with the results, everything you have heard and read, well worth it. But, after about 5 hours of listening to lp's I began to hear the music slow down for a moment then imperceptibly resume speed normally. Could it be from the Walker SST and increased signal? I applied SST to all connections including cartridge leads. It also seems to get worse after a couple of lp's. Nothing else changed and I listen everyday for a couple of hours. I have changed belt too. So, the question is could it be from the Walker SST and increased connection?