Brother Bpac SDK - Access violation with .NET core and .NET 5, but not .NET framework

I'm using Brothers bpac SDK to control a label printer, and I've found that it only works in .NET framework. Using .NET core or .NET 5 gives the exit code -1073741819 (0xc0000005) 'Access violation'. No exception is thrown, so I'm not sure what the issue is.

Moving to .NET framework isn't an issue, but I'd like to understand why. Its my understanding that .NET 5 is a sort of successor to .NET core and framework, so I'm interested to know what might possibly be the issue here.

Sorry if this isn't a lot of information to go on, but if anyone has had similar issues with this SDK or any other libraries, any insight on where to investigate would be great!