If you have gone over all of the steps and have made 100% sure it's not a detergent issue then service repairs are recommended. You can message me here: http://bit.ly/2igAXKH for details.
Do you use powder detergent? If yes, that could be an answer. It could also be excess liquid detergent if you happened to have used too much in a load and it didn't wash itself out through the cycle.
An you're using only HE detergents correct? Happen to have a pic of the residue?
Only HE detergents used. I will try to collect some of the residue and take a pic. The best I can describe it is that it looks like the white-grayish white corrision from aluminum.
I did find a couple of pics on the web of aY shaped brace or framework on the bottom of the tub that was just disintegrating and falling apart. Could this be happening to mine but not to that extent yet?
I mean anything is possible, but in my experiences I doubt it. I will certainly be happy to look into this further though.
By any chance, have you checked the inlet filters to see if there was any build up on them?