When the maximum bundle size is exceeded by a non-bundled message an error is generated and the message is not set. When bundling is configured to small sizes this is very problematic because it is impossible to avoid without serious performance consequences.

JGRP000029: node1: failed sending message to node2 (1413 bytes): java.lang.Exception: message size (1413) is greater than max bundling size (1400). Set the fragmentation/bundle size in FRAG/FRAG2 and TP correctly, headers: FRAG: [id=999, frag_id=1, num_frags=3], UDP: [cluster_name=MainCluster]

Recommendation: Let bundling size limit be just that – the maximum size that bundles will be built to. If a maximum UDP packet size restriction is desired then add that as a separate option. However I don't recommend this because this error is pretty much fatal if the wrong kind of message is exceeding the limit. Once the packet has made it past the frag protocols it is going to be the size it wants to be. Refusing to put it on the network only has bad outcomes because there is no recovery.