Resolution:
Customers are reporting syntax errors on inbound X12 transactions with EDI 5.2 that were processed with out problems with EDI 5.1.  They are seeing errors that look like this:

Node:  060: Name
Context:  Transaction-852 | Loop-N1 | Segment-N1
Location:  Segment:3
Category:  Rejecting
Severity:  Normal
Brief:  : An X12 syntax error occurred. [ID=0x9210014]
Details:  Invalid syntax rules. Rule "" is not acceptable. Segment N1 is defined in the guideline at position 060. This error was detected at: Segment Count: 3 Characters: 1390 through 1725
ID:  0x9210014

This issue occurs because of pre-EDI 5.2 .ecs files containing empty Rules “” which are not allowed in EDI 5.2.0..  

To eliminate the problem, do the following:

1.  For the failing transaction, download the .ecs file from BC to a computer with SpecBuilder 6.2 installed (included with EDI 5.2).

2.  Open the .ecs file with SpecBuilder.  SpecBuilder will immediately try to upgrade the version of the .ecs file to 1.09.  Allow SpecBuilder to do this.

3.  Once the upgrade is complete, save the .ecs file again under a new name (NOTE:  once the .ecs file is upgraded, it can not be used with any other EDI version other than EDI 5.2 and above).

4.  Upload the revised .ecs file into the transaction.

This should correct the issue.

EDI syntax errors occur on previously correct transactions when upgrading from EDI 5.1 toEDI 5.2