The short answer is that it is a Tcl/Tk problem.
The long answer is that this was something that was fixed for a while, then macOS updated and it broke in Tk again. Tk development is a bit behind on macOS and it's difficult to keep in sync as Pd requires an older version of Tk to support old versions of macOS back to 10.6. Fixing this will require yet another manual patch to the Tk 8.5 source code which I cannot even build on my macOS 10.14 system any more.
Message: 3Date: Fri, 8 May 2020 19:35:28 +0200From: "Josef (Seppo) Gruendler" <seppo@mur.at>To: pd-list@lists.iem.atSubject: [PD] pd crashes on reopening file with out of scope coordinatesMessage-ID: <BD2C1A0A-D89A-4EF5-BFF4-F26E10598BC7@mur.at>Content-Type: text/plain; charset="utf-8"Hopefully this had not been mentioned before, but didn't find something about this:Tested under Windows 10 and OSX 10.14 and 10.15 and pd 50.02If a patch is edited it witha second Display attached and this is missing later on and the patch contains negative coordinates like:#N canvas -1374 447 879 555 10; pd crashes on osx and the file does not open on windows 10 (at least not my and my students machines)If we edit it to something existing like #N canvas 50 50 879 555 10; it works fine.Don’t know if this is a tkl/tk or pd problem ?bestSeppo----------------------------------------------------------------Be green keep it on the screen! Josef (Seppo) Gruendler