If you create new CR using web console (potentially using command line as well, but I haven't tested that option) and specify the storage size as something that won't pass the parsing regex, operator gets into crash loop with following exception:

/opt/rh/go-toolset-1.13/root/usr/lib/go-toolset-1.13-golang/src/runtime/asm_amd64.s:1357
panic: cannot parse '4Gb': quantities must match the regular expression '^([+-]?[0-9.]+)([eEinumkKMGTP]*[-+]?[0-9]*)$' [recovered]
	panic: cannot parse '4Gb': quantities must match the regular expression '^([+-]?[0-9.]+)([eEinumkKMGTP]*[-+]?[0-9]*)$'

However, editing already created CR doesn't lead to such crash, i.e.:

1) create CR with "2Gi" (correct string)

2) Change it to "2GB" (incorrect string)