I’m trying to add SRR to a legacy Angular application that we have just upgraded to Angular 18.
We have successfully ran:

ng add @angular/ssr

When running ng serve we are getting the following error:

3:06:35 PM [vite] Internal server error: Cannot read properties of undefined (reading 'regular')
      at prepareForHydration (node_modules/@angular/platform-server/fesm2022/platform-server.mjs:16983:26)
      at eval (node_modules/@angular/platform-server/fesm2022/platform-server.mjs:17036:3)
      at Generator.next (<anonymous>)
      at fulfilled (.angular/vite-root/transparency-portal/chunk-7PH555RD.mjs:74:24)
      at _ZoneDelegate.invoke (node_modules/zone.js/fesm2015/zone-node.js:365:28)
      at _ZoneImpl.run (node_modules/zone.js/fesm2015/zone-node.js:111:43)
      at eval (node_modules/zone.js/fesm2015/zone-node.js:1192:40)
      at _ZoneDelegate.invokeTask (node_modules/zone.js/fesm2015/zone-node.js:398:33)
      at _ZoneImpl.runTask (node_modules/zone.js/fesm2015/zone-node.js:158:47)
      at drainMicroTaskQueue (node_modules/zone.js/fesm2015/zone-node.js:577:35)