Banana as a result of a sour mash?

I did a sour mash at work, started the mash last Monday, brewed on Wednesday, so a 48hr sour mash. I mashed in at 152F, and it never got below 105F. I mashed out on Wednesday with boiling water, sparged as normal, boiled 2hrs, used very little hops (6oz of Magnum in 7bbls), knocked out normally, aerated normally, pitched a rather large pitch of 1728 at 66F and fermented at 68F.

It started at 9.4P (around abouts 1.037), finished at .7P on Friday (about 1.003). So now, on Sunday, most of the yeast has dropped out, and I am getting a fairly assertive banana ester, both in the aroma and the taste. The aroma is basically a sour banana, and the taste is sour across the middle of the tongue, and banana on the outside and in the finish (strongest in the finish).

Has anybody gotten this from sour mashing? I have never gotten isoamyl acetate out of scottish yeast. I know ferrulic acid plays a role in isoamyl acetate, and the acid rest is low 100s, but the enzymes should have been denatured during the sacc rest right? Could the yeast have been affected by the low pH during fermentation? Has anybody else noticed this in a sour mashed beer?

Experience or theories are welcome. This doesn't ruin the beer by any means, but it isn't intended and next sour mash I don't want to end up with the same result. Thanks.

what yeast did you use on this?

I thought you were doing sour mashed berliner, why would you use a scottish yeast and not something clean like chico or a german ale yeast?

Scottish (WY1728) is one of the cleaner yeasts that I have used, and the one I have easiest access to. I find it about as clean as chico.