MCH3602 from QSYGRHLR?

Folks:

I've got a program on a customers system that's doing a MOVOBJ ... and, sometimes, it's failing with a MCH3602 error.

IBM is saying that it's our program that's at fault ... but I can't see how. We're just invoking MOVOBJ with parameters.

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MCH3602 Escape 40 08/02/16 07:18:24.278876 #cfochkr 0001C8 QSYGRHLR QSYS 0004
Message . . . . : Pointer type not valid for requested operation.
Cause . . . . . : A pointer type was not valid for the requested operation.
Recovery . . . : Correct the pointer use.
CPF9999 Diagnostic 40 08/02/16 07:18:24.289705 QMHUNMSG *N QLIMVOBJ QSYS 03BA
Message . . . . : Function check. MCH3602 unmonitored by QSYGRHLR at
statement *N, instruction X'0004'.
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The phrase "Pointer type" is significant, I'm sure.

This is running on 7.3.

Any ideas what might be causing this?

Thanks!

david