I don't want to go too far down the ol' Szykman rabbit hole with this, but, I did a bit more Orders Solver exploration,

I've read a few articles on convoy paradoxes, involving Szykman, and they're usually these horribly contrived and convoluted things wherein A gets convoyed to B, B convoyed to C, C convoyed to A, etc. And there may be any number of supports involved for the both the convoying fleets and supports for the armies attacking their destinations. Makes my head hurt reading them...
First, to Jack, if AEG s Gre-Ion there's no issue/paradox at all in my view. The convoy is blown-up and the army stays in Tunis. (However, there's a twist to this, which I found out in my second test!).
NoPun's point that, in effect, the army's movement order is converted to a Hold - before adjudication and also reflecting what the in-game message says - similarly to how any illegal order is converted to a Hold before adjudication, is the right way to look at it. For example: A Bur-Mos & A Par s Bur does result in Bur holding AND receiving a valid support.
Also, per the rulebook, if there is another, alternate convoy route for the same army order (imagine Ionian being split into an eastern and western sea zone) and Italy having a fleet in each zone. Tun-Gre is ordered with both fleets ordered to convoy the army. In that case, the army would cut any support Austria's F AEG attempted to render, since the convoy has an alternate route which wasn't disrupted. The army movement wouldn't succeed though, unless sufficiently supported.
I peeked at this
article on Szykman and noticed the following:
"If a situation arises in which an army's convoy order results in a paradoxical adjudication, the turn is adjudicated as if the convoying army had been ordered to hold, except that that army may not receive support to hold."
So we may be using a different implementation of Szykman (or Szykman has itself changed over the years) as we saw that Italy's A Tunis was indeed able to receive support to Hold, in the case where the convoy was cancelled due to a paradox.
But, lol....here is the result of my new Orders Solver test. What happens if?:
Turkish F AEG s Austrian F Gre-ION
Italian F ION c Italian A Tun-Gre
Italian F WES s Tun
French F NAf s French F TYN-Tun
Note, there's no Szykman here. So there's no cancellation of the convoy and no conversion of A Tunis' order to Hold before adjudication takes place. So the question becomes, is A Tunis still eligible to receive support as it was under Szykman?
Answer in spoilers. You might be surprised!
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