illegal instruction constexpr v1712 v1806

Trying to compile a new solver on windows 10 bash with ubuntu. Compiler returns an error saying illegal instruction constexpr. This has occurred on versions 1712 and 1806 in the header file floatScalar.H. I believe it has been a repeated issue from what I have seen on the forums so others will probably be able to provide more information. I don't know if this is a version issue because I updated all my compilers. I only come because the only solution I have seen found to this anywhere is revert to OF5. I have seen this exact issue reported on v1706 as well.