What happens that makes you think it only has 5 frames of armor? You're the second person to mention a limited number of armor frames so I did some more testing.
Goro's s2 is +2 on block. The bot is set to reversal Invisibility and auto block. I hit it with s2 and then follow up with normals of different lengths. d1 is 6 frames so it should be hitting on about the 4th frame. f3(the last move in that video) is 16 frames so it should be hitting on the 14th frame or later. Everything I did ended up hitting armor. Nothing stuffs the move, it either hits the armor or he blocks it
I tried testing the start up with Liu Kang. His f213~stance switch is supposed to be +6 and his f1 is 6 frames so I should be hitting around the first frame and I always connect with armor.
All the testing I've done and everything I've seen seems to imply that the move has 16 frames of armor, and as soon as the armor's gone you can block. If anyone has video that shows otherwise I'd appreciate it if you posted
Thanks for mentioning X-ray! I think I mentioned it in the first post but the armor hit always takes damage, you don't get the damage free hit until after the move finishes so you can usually take a hit with your armor and still absorb damage later. X-rays have armor break so they go straight through the Invisibility. The move gets stuffed so you don't get a hit without damage and you take full damage from the X-ray. X-rays and moves/strings that hit twice within 16 frames are the only way to punish this as far as I found so far