During package submission process, Uwe said:
need to reduce the check time, this time we see * checking tests ... [16m] OK which is really too much as the overall check time of a package should be less than 10 min and this may be killed during the checks.
IIt's much shorter on my machine (macOS) and from what I could see, this seemed to be on Windows (from my testing of the package before submission using WinBuilder). Regardless, something we need to include in our next submission to CRAN (likely patch).