Eternabond over butyl tape

There is a current thread in the "tech issues" section, currently, on Eternabond and bond failures.

You have detected the cause of many bond failures with the tape. The surface needs to be cleaned and sealant residue removed. Acetone won't remove some residues. I've had good luck with mineral spirits followed by lacquer thinner. You need to be careful of paint surfaces when using lacquer thinner. I think some folks have good luck applying the tape over prior sealants because they leave a cleaned surface outboard of the sealant joint and the tape is able to adhere to those surfaces.
If it was me (and it was), I'd remove any prior sealants and all the residue before applying the tape.

I have used EternaBond over the years. It sticks to most anything except silicon caulk. Were it me, I would do as you have done by cleaning with acetone then tape over it. I like to use Eternabmd that will give me a two inch lap on both sides of the joint I'm tapeing. One inch absolute minimum.