This is a warning only and should not cause you any harm. Historically SAP could store 35 characters for a customer/vendor names,street name, etc in kna1, lfa1, tables, but 40 in the address table. There were situations in ECC that is the Customer/Vendor would not be transferred or printed properly (fully) and the name on the output or idoc was truncated to the first 35 characters.
To my best knowledge this warning can be ignored - should be possible to disable it in spro - and you can include in your test scripts how the system outputs long names on gts forms/idocs/etc.. for the piece of mind..