I only mentioned this because I was reminded of a horribly bad Fox TV series in 1997 (so bad that the final 5 episodes out of 13 were not aired until the year 2000) called Roar.
You mean the general understanding of Late Antiquity and Early Medieval is poor at best, and hilarously wrong more regularily?
Where the world is going?
As we all known, within the decade the Romans would be gone for good.
In fact, they were already in the process of abandoning the province. Since 383, most of western and northern Britain was already abandoned, meaning that the more or less romanized Brittonic peoples being raided over were already on their own,
Déisi beggining to settle in Wales, Scots raiding as far as Midlands.
For what matter Irish raiders and settlers, Rome was already gone for good.
No, my thinking was over campaigns that might have been launched pre- or post Agricola, but long before the End Times eof Rome (i.e., well before 383 AD).
Well, you do have some strong hints that it might have been the case c. 100 AD, in the usual fashion of supporting the claim of a clientelized prince, in order to stabilize and impose Roman influnce on a given region (as it was made elsewhere).
Later, in the IInd century, that's still a technical possibility, seeing that Septimus Severius did launched a campaign in Caledonia and planned another before he died.
But it was really following the model of "beating peripherical people into sumbission" which was prevalent at this point, in order to make Caledonians and Maetes stopping their general rebeliousness, raiding and to eventually enforce their clientelisation.
Now, why would have it been the case for Ireland? I could see some trouble-maker, managing or trying to gain local power or to unify some of the chiefdoms in Ireland, and importantly dirsupting the political balance up to creating enough troubles leading to raids or even revolts in Britain (you may had parenty relations between some Irish and peoples as Brigantes IOTL); and ending being reminded of his position. Namely, corpsy.
But historically, Ireland seems to have been relatively calm on these manners. I'm not sure there's a good reason why : we don't know of any major roman operation, even the possibility of such, after Agricola nevertheless.