Further to the above post, the script deleted symbols that I had created or modified, concrete blocks and gas heater for example, from my VW files. I assumed 'removing the record' would remove some attached data, not the actual symbol. Luckily I have the original 2018 file to keep working on.
I was having the same problem with 2 sheets (out of many) in a 2018 SP5 project crashing VW on DWG export, I imported it into 2019 SP2 and it still crashed. I ran the above script in my 2019 file and the 2 drawings exported to DWG without crashing. Seems like this export DWG / negatively scaled symbol issue needs to be fixed in the next 2019 service pack?