SQL Server 2017 log file growth with memory optimized table
First of all, if you use durable memory-optimized tables, everything from the memory-optimized side will be fully logged - the database recovery setting is not respected. 

Next, is your 2017 install fully patched? There have been a number of fixes to the In-Memory engine since RTM. 

In order for the log to be cleared of memory-optimized transactions, they must also be written to the checkpoint file pairs. If the CFPs needed to be expanded/added, and the drive/volume that hosts them can't do that, then the transaction log cannot be cleared.