I think the glue is coming off because you didn't degrease it. Something is stopping it sticking.
Standard practice for bonding ANYTHING: it needs the surface to be keyed and it needs to be free of grease or debris. So key both surfaces with 400 grit and thoroughly degrease it with an alcohol based degreaser. DO NOT use acetone because it will attack the resin in the carbon fibre, isopropanol is best.
This is how we bond all composites at work and your wheels are no different.
Zipp actually specify you can use acetone on their FAQ.
If the rim is new, wipe it down with alcohol or another solvent such as acetone, which is also recommended to remove old glue. The Zipp carbon rim can be cleaned with any solvent that will not harm epoxy. Zipp Carbon rims are ready to go at this point and require no further preparation.
I was sure it said not to sand the rims, but I can't find that anywhere.



