Reproduction steps:

1. Build & run the attached project with Master configuration to x86 architecture
2. It will immediately trigger a breakpoint with following output:

Exception thrown: 'UnityEngine.UnityException' in WinRTBridge.dll
An unhandled exception of type 'UnityEngine.UnityException' occurred in WinRTBridge.dll
Additional information: Tag: testtag is not defined.

Unhandled exception at 0x01C06D75 (nt.dll) in nt.exe: 0x00028F94.

Unhandled exception at 0xECF98B80 in nt.exe: 0xC00000FD: Stack overflow (parameters: 0x00000001, 0x08B12FF8).

Unhandled exception at 0xECF98B80 in nt.exe: 0xC0000005: Access violation writing location 0x08B10FF8.

Note, that when deploying without debugging, title silently crashes. Not reproducible on SDK 8.1

Reproducible with both 5.2, 5.3 and 5.4

Note, not reproducible with Release/Debug configuration