After upgrading Gen 7.6 to 8.6 IMS transaction exported data is truncated

Products

• Gen - Run Time Distributed
• Gen - Workstation Toolset
• Gen

Issue/Introduction

Gen Unix transaction uses 'C' External Action Block (EAB) to call a Gen IMS transaction via MQ.
After upgrade from Gen 7.6 to Gen 8.6 the IMS transaction export group view data in the returned MQ message log is truncated.
40 records are being processed and from the 36th position to the 40th position the expected data is missing. The string SOHfETX string is shown from when the data is missing. 
SOH - Start of Header, ETX - End of Text, and the "f" character is inbetween them.

Environment

Gen Run Time, Blockmode

Resolution

In comparing the 7.6 and 8.6 generated code, it was noticed that the working 7.6 Dialog Manager had been generated with MAX-SEG-SIZE=1500, but the non-working 8.6 Dialog Manager had been generated with MAX-SEG-SIZE=1280.
Regeneration of the 8.6 Dialog Manager from the CSE using Business System Environment Parameter "Max Seg Size (IMS)"=1500 and rebuilding the load module with the z/OS IT resolved the problem.
All other transactions work successfully with a value of 1280 and only this single transaction needed to be generated with a value of 1500 (probably due to an increase in the size of the export group view at some time).