Single Pin Sights

[BrentLaBere]

Likely to be anchor point. This can be caused by string stretch and shooter error both. Sure doesn't take a lot.
1" different than before doesn't require a lot of change in you and what you're doing, whether it be the srings stretching that causes it or just a different anchor point. The release you use could effect it as well, especially if it is an index finger type, not cinched up exactly the same, or wearing a bit. So many things could cause 1". Now if it was 3"-6" that is different.
I can purposely torque my bow and at 60 yards get a different POI up to over 6".

I wouldn't change anything until you shoot several times and verify repeatability of a low POI.
Of course, changing the slide to get that 1" back, aint no big deal any way. So changing it and then finding out the next time out you had to go back to where it was for the last 2 years will answer your questions.

What is your sight and release? How big is the sight pin? (.010, .019 etc)

HHA .019 - True Fire Hardcore buckle fold back. It does have some wear on the same hole I attach my wrist strap. I wear the same pair of finger less gloves every time I shoot in the off season to match what Ill be wearing during the hunt.

 

[Bayerc]

I have had similar issue. I took my bow back to the shop and re-chronograph and checked the draw weight. This time is was the string loosing up, the other time it was my anchor point