Q) Have there been a change or some errata to the S25FL164, and where do i find information about this?
A) There is no errata associated with this part. I have checked our internal database also and did not find any errata. For your information if at all there is errata related to device it will be mentioned in the datasheet under Errata section.
Incase if you are going for new designs please note that it is Not Recommended for New designs (NRND).
Can you tell me from how long you are using these boards. As you mentioned it could be timing issues. Are you programming using third party programmers or In system programming.?