Turned out I then hit another error which may worth @alfarzan investigating and other R zip file submission people that have recently upgraded to xgboost 1.3 and are getting submission errors also trying.
I upgraded my local version of xgboost to 1.3 which for R users was released on CRAN in the last week. Anyhow after the upgrade I’ve not been successful in making submissions from locally trained zip file, even though they pass all the local tests as per the zip instructions (and I’ve been making successful zip based submissions in previous weeks with xgboost 1.2.)
Anyhow after I downgraded my local version of xgboost back to 1.2, retrained, re-ran tests which again passed and then reloaded my submission then worked.
Could it be that AICrowd is loading xgboost 1.2 for R users and the models trained with the new 1.3 version have incompatibilities causing submission errors? In which case guess I need to specify my version of xgboost in install packages.