Inconsistent exportRecords behavior

[Wunsei]

I posted back in October regarding the exportRecords function no longer working, but after a day or two, it suddenly started working again. It worked most of the time, but I would occasionally still get the following error:

Error in redcap_error(x, error_handling = error_handling) : 
  400: ERROR: An unknown error occurred. Please check your API parameters.

After restarting my computer, this error would usually stop occurring. Sometimes I would have to wait, but it would usually resolve itself within a day or two. However, I just changed to a new PC and the error persists.

Why might this be happening? I change nothing in the code -- sometimes I get the error, other times I'm able to pull all the data with no issues.