I was reading technical stuff regarding the topic compression to satisfy my own curiosity.
I did come across something that may be of some help here.
Again assuming there is no compression.
Source What Is Engine Compression And How Is It Tested? - Apex Tool CompanyQuote:
Consecutive Low Compression in All CylindersThis could happen because of fuel washed cylinders, when too much fuel is introduced into the engine and all oil has been washed off the walls of the cylinder. The oil creates a sealing effect between the ring assemblies of the piston and the cylinder walls of the engine block. When this thin layer of oil is washed off, the engine compression escapes into the crankcase. Engines with a flooding problem usually show this behavior.
Just trying to offer possibilities.

