I've noticed that an unusually high number of my attempted send transactions between my nodes (which is currently only 6 at most, but never less than 4) will not broadcast regardless of the amount of time I wait. I end up having to eventually abandon them to return the funds from the wallet I am trying to send them from. I have noticed no specific correlation between sender and recipient (like a single node always being unable to send or receive) and have noticed that every successful transaction is broadcast and appears in the memory pool pretty much immediately after sending.
Is there any specific cause for this? Maybe the fact that I'm currently limited to such a small # of nodes?
Have used getnewaddress to generate every address that has successfully and unsuccessfully received coins so I find it difficult to believe the actual addresses can be the problem as they should all have been derived from valid keys.