Hello,
we found an issue when creating new document reports based on standard (i.e 206, 205, ...) on Business Central On Premise 2019 Release Wave 2. I tried also with 2019 Spring Release with same results.These standard reports are printed on the invoice language as expected. If the document has ESP as language code the report is printed in spanish, and is the same for english, ...
The problem appears when we make versions for these reports. If the user session language is spanish then the reports are printed as expected, ESP language documents are prnted in spanish and ENU language documents in english. But if we change our user session language to ENU, then the ESP language documents are mixed between spanish and english. I found that this has something related with labels, the FIELDCAPTION values are well translated.
Examples:
Spanish document with spanish user language. Everything ok.

English document with spanish user language. Everything ok.

Same docs., but changing user session language
Spanish document with english user session language. Please note that report labels were fine translated when user session language was spanish.

In summary, when user interface language is ENU our extension report labels are not translated correctly while FIELDCAPTION labels are ok. And with standard reports (206, ...) the problem dissappears. Take into consideration that this is done with no modification of the reports, just export standard report to 5XXXX and change on report selections and the translation fails.