Shower Waterproofing

Hey Isaac, first off thanks for creating the Youtube videos and this site; as a somewhat experienced DIYer and former handyman, I think I can figure a lot of things out... but your guidance and the help from other members on this board makes things a ton easier, and helps to build confidence in doing things the right way!

So, to my project: I'm building a 36x60 shower stall, and using kerdi membrane over sheetrock walls. I put up the sheets and pan last night, and ran into an issue with one of the corners. Specifically, I'm using a single sheet for a corner section, and found that on the lower portion of the corner 1.) I didn't get the membrane fully pushed into corner, and 2.) have a section with bubbles/wrinkles that didn't adhere to the thinset (see pictures below for both):

I'm using Laticrete Multimax as my thinset, Kerdi band and corners for the specified joints, and figured I'd put a coat or two of Hydroban liquid over critical seams (drain flange, banding seams, niche seams, probably up 12-24" on the walls). Finally, I'll be using 8x24" tile for the walls.

My question is how should I approach fixing the loose corner and bubbling issues (if at all)?