I know, this is not an EOS problem, but EOS uses per-channel-priority packets with an alternating start code of 0xDD, but many software does ignore the start code and read this data as DMX data, which will cause flickering in the software.
I am not entirely sure, that EOS uses these packets for, because you can not specify a priority for a single fixture, so why not have the option to disable the per-channel-priority packets?
Per-Address Priority is used for addresses that are not patched in Eos. Eos, ColorSource AV, EchoTouch, and Paradigm all use this functionality to limit sending data for addresses not actively being controlled.
Some products, like Paradigm have the ability to manipulate the priority further similar to how you mentioned in the last sentence.
However, in order to support non-compliant products there is a ticket written up to provide an option to disable the per-address priority. I will add your request to this ticket. Also, because this is a recent addition to the Eos Forums, Feature Requests should be entered here: Eos Family Feature Requests - Eos Family Consoles - ETC - Community