I've encountered the same problem...still digging some info...have been told that this is actually happening not because of e85..but because of unleaded additives.
Fact is builders screw the tradies... so everyone takes shortcuts to compensate...have you seen the joints on a ceiling in new houses.... ive never in my life made a ceiling look so bad... They use boxes cause they cant trowel and only put 2 coats instead of 3.
Surge tank set up is roughly 10 mnths old, and have been using e85 for about 8 mnths now. I believe that the cause is from e85, I will also pull the petrol tank out and have a look at the submersible intank hose too. I believe that maybe even worse.
Ok guys..Had the ute up on the hoist on Saturday...was having a look at the hoses coming off the Surgetank and found what I believe, E85 was doing to my hose. Am now sourcing a E85 compatible set now. Just a heads up for everyone else that's all.