StateOfTheArt issues with v28

I've finally got around to upgrading my old v22F ClassicWB setup to v28. The install went fine but if I launch and the bundled StateOfTheArt demo and quit with F10 I get a mix of errors: usually an Illegal Instruction ($10) or a HALT3 in WinUAE that halts the system.

I'm using WinUAE 3.5.0 (2017.06.15) 64-bit. The configuration is close to default A1200 but with 16MB Fast RAM, and maybe 030 CPU with FPU. I'm using WB3.1 during the upgrade and KS 3.1 (40.68). It's using WHDLoad 18.2, though I've also tried 18.3.

My v22F install works fine with exactly the same WinUAE setup, just swapping over the bootable HDD image. Always a clean return to WB without errors.

I've tried been through all v28 version from LITE to ADVSP, but without any luck narrowing down the cause.

Has anyone else seen this? Any suggestions on what might be causing it?