There are a bunch of errors like this in RB:
```
Expecting : in parser function definiton
AssertionError: Expecting : in parser function definiton
at Console.assert (console.js:95:23)
at TemplateHandler.resolveTemplateTarget (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tt/TemplateHandler.js:480:13)
at TemplateHandler.onTemplate (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tt/TemplateHandler.js:110:17)
at AsyncTokenTransformManager.transformTokens (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/TokenTransformManager.js:626:17)
at AsyncTokenTransformManager.onChunk (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/TokenTransformManager.js:399:17)
at emitOne (events.js:96:13)
at SyncTokenTransformManager.emit (events.js:188:7)
at SyncTokenTransformManager.onChunk (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/TokenTransformManager.js:983:7)
at emitOne (events.js:96:13)
at PegTokenizer.emit (events.js:188:7)
at emitChunk (eval at <anonymous> (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tokenizer.js:1:0), <anonymous>:20160:25)
at peg$c33 (eval at <anonymous> (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tokenizer.js:1:0), <anonymous>:390:11)
at peg$parsetlb (eval at <anonymous> (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tokenizer.js:1:0), <anonymous>:3208:12)
at Object.next (eval at <anonymous> (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tokenizer.js:1:0), <anonymous>:1922:14)
at tokenizeChunk (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tokenizer.js:293:20)
at PegTokenizer.tokenizeAsync (/srv/deployment/parsoid/deploy-cache/revs/48be65b94d0147ab21c5bc9390bb168f30b98084/src/lib/wt2html/tokenizer.js:306:2)
```
Sample title for which it happens: `/de.wikipedia.org/v1/page/html/Wikipedia%3AProjektdiskussion%2FPRD-subst%2Fpre`. The `x-triggered-by` header suggests this might be coming as a result of a faulty template transclusion:
```
mediawiki.revision-create:https://de.wikipedia.org/wiki/Wikipedia:Projektdiskussion/New_filters_for_Recent_Changes_-_Beta_deployment_schedule_for_your_wiki,change-prop.transcludes.resource-change:https://de.wikipedia.org/wiki/Wikipedia%3AProjektdiskussion%2FPRD-subst%2Fpre,change-prop.retry.change-prop.transcludes.resource-change:https://de.wikipedia.org/wiki/Wikipedia%3AProjektdiskussion%2FPRD-subst%2Fpre,change-prop.retry.change-prop.transcludes.resource-change:https://de.wikipedia.org/wiki/Wikipedia%3AProjektdiskussion%2FPRD-subst%2Fpre
```
I haven't investigated, so if this is not a genuine Parsoid problem, but a template fault, excuse the noise :)