Hi,
That was a surprised as you've communicated to us on 6-Sep-2019 that you still seeing the same issue on Quartus 19.2.
Anyhow, please let us know if your system configuration meet the minimum requirement of Quartus 18.X RAM processing design?
You can check from below document:
https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/rn/archives/rn-qts-std-dev-support-18.1.pdf
As we can't duplicate your error internally, I check thru existing internal database and came across this issue should caused by insufficient of RAM. Please click on above guide and go to section 1.3 (Table 1) for more details.
Thanks,
Joseph