Shift shaft too Short

Hello I’m new to the site and was sent here by marine engine dot com. I’m trying to line up the shift shaft in Alpha one drive with the transom gear linkage slot but the shift shaft is too low. They barely fit and I don’t think would stay together on the water. Here is a video describing the issue. All shift shaft part numbers are the same so they don’t come in different lengths. Any one had this issue before?
https://youtu.be/Z7gcppQFsf4

Have you confirmed the shift shafts are identical? Could A shaft be shorter/different then B shaft.

I would start there.

I have seen in a couple of rare cases. The lower bushing in the bell housing has worked it way up about an 1/8 of an inch causing loss of reverse engagement. This allows bell housing vertical shift shaft to be to high. Not saying its your issue but if A's shift shaft is identical to B's shaft then you have to look elsewhere.

Only other issue could be Bell crank where the Lower shift shaft engages. (spline side of lower shift shaft)

If the bell crank is sitting to low or is a different size in drive A compared to B this would lead to the shaft sitting lower

Thanks for the reply. You nailed it in your post in third paragraph. The upper slotted piece had moved up when I first installed the outdrive. I guess it came out of forward and I used too much force pushing the drive in which shoved the upper part bushing upward. I’ll remove the drive and repair tonight.