Travis build exited with 1 but local check with devtools is fine

I have an R package that was passing all builds successfully and randomly started to fail. I've pondered where the problem is at but I can't seem to fix it.

Here is the travi.yaml from the package

Here is the failing log of Travis-CI

Here is the last log the passed (about 2-3 logs behind the last fail)

I think the fail might be related to line 1495 from the last log that passed: The command "for name in $(find "${RCHECK_DIR}" -type f -name "*out");do echo ">>> Filename: ${name} <<<";cat ${name};done" exited with 0.

which does not appear in the failed log from above. After thoroughly checking my tests with devtools:

R CMD check results
0 errors | 0 warnings | 0 notes

I don't know what it might be. I thought it was related to some examples taking too much time (some examples pass the 5 second thresholds, so I comment them out but the failing persists.

Any ideas?