I spent some time looking at a couple dozen articles and NFL transaction registers from 2024 and 2025 and I think both important elements of your recollections are probably incorrect - at least starting in 2025.
First, no issue that the IPP offers a +1 roster exemption during the offseason roster max (90+1) and in-season practice squad max (16+1), for a period of up to 3 years for "qualified" international originating players.
I think the gist of your question would be 1) do you need to waive a player at the 53-man roster deadline before adding him to the practice squad as your IPP exempt player and 2) once added, can he then be poached by another team?
Second one first. I believe the answer is YES, the player may be claimed off of a team's practice squad starting in 2025 but needs to go directly onto the claiming teams 53-man roster, as any practice squad claim would have to. There was a 2025 article by the Falcons Director of Football Communications that addresses the poaching thing as a recent 2025 "recent change."
The article says "One recent change to the international player rules is that (Lenny) Krieg (Atlanta's 2025 IPP exemption) is now eligible to be signed off the Falcons practice squad to another team's active roster at any time. Previously, IPs were not permitted to be signed from a practice squad to another team's active roster." I would hope that if a team DirComm is going to be posting something on an NFL team's website they would run it past a knowledgeable in-house set of eyes before publishing. So, given the specificity of the statement I'm considering that to be pretty authoritative.
That said, each team can protect up to 4 players per week as "unclaimable," or put a PS player onto their active roster up to 3 times per season, so a team could make an IPP "unpoachable" if they chose one of those options.
Second element - must Eagles waive (or otherwise somehow put the IPP "at risk") before putting him onto their PS, I am concluding YES they will have to do so.
Here though there is disagreement with the internet search sites. If you read Wikipedia (inquire "International Player Pathway"), it clearly says the player must go onto the 53 Player Roster or clear waivers to go onto the PS with an IPP exemption. On the other hand, if you query Copilot (inquire "do ipp nfl players need to be waived before they can be placed on the team practice squad"), it is very clear that the player does NOT need to go onto waivers because the Pathway has a direct placement onto the PS for the IPP candidate.
So here is what I did. Took 10 players off of the NFL.com roster of players that were part of the IPP during 2024 (7) and 2025 (3) and looked at their player transaction histories in PFF for the 2024 thru current. Of the 10 players, 7 were reported by PFF and NFL.com as having been waived during final August cutdowns during their first year in the IPP. Five were "reclaimed" by the same team the following day and placed on the PS as an IPP (Laekin Vakalahi-PHL, Alex Hale-GB, Killan Zierer-HOU, Mapalo Mwansa-CAR, and Lenny Krieg-ATL).
When NFL.com reports these players as waived, the terminology used was "Terminated vis Waivers, all contracts." So, I wondered whether this was perhaps an internal, administrative process where the existing contracts were terminated so they could be added back with a PS contract, but maybe player control wasn't really "at risk." I wondered this in part because Copilot seemed to be troubled by the term "go thru waivers" and talked about there being a process to directly place the player onto the practice squad. But this was disproven (IMO) by the other two players. In those cases, Luke Felix-Fualalo was put on waivers in 2025 by Seattle and claimed by the Eagles (after they waived Vakahali for a second year); and Louis Rees-Zammit was placed on final waivers and claimed the next day by Jacksonville. So that to me means they were at risk at cut down.
For the record, of the remaining three of 10 players, two (Bayron Matos-MIA and David Olajiga-LAR) were waived and seemed to stay out of the league until the next contract year when they resigned a futures contract with their previous teams; and on players was not put on waivers their first year but was placed onto Injured Reserve instead (Travis Clayton-BUF).
So my conclusion is that it the Eagles want to protect Bernard, he will have to go onto the 53 man roster, injured reserve or be put at risk to waivers. Once on the PS he would remain at risk unless protected by one of the Eagles "non-poach" techniques.
To be authoritative I suppose we would have to ask one of our journalistic buds to pose a question to Howie during an interview.