M6100 (xcm8924x) upload to ISP being limited?

[MotoCP]

I have an M6100 with a xcm8924x blade in it. I can't seem to get the upload speeds to my ISP to work correctly via SFP+ but rj45 works just fine. I am using 2 Netgear branded axm761 SFP+ 10GB modules and a 10GB fiber cable spanning approximately 120ft max (OM3 LC multimode duplex) but for some reason I am still being limited to 250-300Mbs upload to ISP via the fiber cable and yet if I use rj-45 I can get full upload speeds to ISP (symmetrical gig speeds via at&t).

At first, I had only 1 axm761 that I had plugged into the switch and then a cisco one on the desktop end but that wouldn't connect at all, so I got a second and it arrived yesterday to throw in the desktop side and now it actually connects but I am being limited on the upload. I've tried to search for an answer but I can't seem to find anything about this or even closely related to it so I am hoping someone here will be able to help me. 

I'm sure anyone who clicks on this post will already know what hardware I have but here is this just incase:
Netgear M6100 MODULE 24x10GBASE-T and 16xSFP+ (shared) | NetSolutionWorks.com (netguardstore.com)

(and I do apologize if I have put this post in the wrong spot or doing something wrong with the post itself, I am still pretty new to forums)

[schumaku]

Reads like a ubiquitous fiber cabling issue.

Correct fiber, the typically blue LC/UPC connectors on the modules (not the green LC/APC), properly cleaned?

Fiber link and fiber splices and patches are tested and measured accordingly?