I’m reloading for my 44. I haven’t kept close track of how many times I’ve loaded the brass because most of the loads have been very light. About 15 g of 2400 with 180 g plated bullets. I bought a new lee trimmer so the last batch I cut to 1.272. A little under the recommended trim length but that was what I need to cut them all square. I loaded about 75 with 18.5 g of 2400 and 180 g win semi jacked hollow points with light crimp (don’t like them very hard to keep square with heavy crimp). They shot ok but had to load one at a time. The light crimp wouldn’t hold the bullet still by the 4th shot the 5th was out 1/16”. Anyway I just cleaned and inspected the brass. It now measures 1.260 to 1.265. Is this normal?

If you haven't resized the brass it will be shorter than the lenght you trimmed it. Resize and see what you have.
What happens is the brass expands to the size of the chamber, as it grows out it shortens the lenght a little. Then as you resize the brass it will lengthen. The brass is moving in each action.

Brass shrinkage is normal as it ages!

Shrinkage in straight walled cases such as revolvers (357 & 44mag, etc) is a common occurrence and normal - more so if you reload.
Just the brass flow on tapered and bottle-necked cases moves the brass forward and so these tend to grow.