Was this ever resolved? I have this exact issue. No matter what I set the MTU to.. it's always 16 bytes too large.

Thank you for posting this. I just had the exact same problem. Switched from policy-based to route-based VPNs and lost ASDM/SSH access to inside interfaces. Couldn't figure it out.   Removed the http/ssh commands and re-entered them. Boom. They work ...