My sister's applied for the pcc in early 2017, before OP, for her PR application and it did not have dates on it, so this is very strange.He clearly mentioned that he got pcc for 2012-2014
But not for 2010
So this rejection is only possible if dates were mentioned on his pcc
I think now Malaysia has changed the format and issuing pcc without dates
Perhaps, even though the dates are not on the certificate, they are verified by IRCC contacting Malaysian authorities directly.