Some users are getting this error while we are testing an update from 8.4 to 8.5

I am not able to duplicate the error myself but it comes up for them in various places when printing or importing data.

Any idea where to look to start troubleshooting it? Here is the client side log, I didn't see anything on the server. The error keeps repeating once it occurs until the client is forced closed.

2019-05-24 10:58:54 BF-1 dumping stack due to wn != g_wn (1)...
2019-05-24 10:58:54 BF-1 --------------------------------------------------
2019-05-24 10:58:54 BF-1 0 0x00757E63 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 1 0x007576A7 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 2 0x006C9D01 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 3 0x006CA561 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 4 0x006CAE93 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 5 0x00586E7B - 0x0000000000000000
2019-05-24 10:58:54 BF-1 6 0x00775227 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 7 0x00777D14 - 0x0000000000000000
2019-05-24 10:58:54 BF-1 8 0x754A62FA gapfnScSendMessage - 0x00000000754A5FC8
2019-05-24 10:58:54 BF-1 9 0x754A6D3A GetThreadDesktop - 0x00000000754A6C63
2019-05-24 10:58:54 BF-1 10 0x754A77D3 CharPrevW - 0x00000000754A7694
2019-05-24 10:58:54 BF-1 11 0x754A789A DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 12 0x007690A4 DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 13 0x005A53AC DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 14 0x005A8394 DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 15 0x00587B31 DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 16 0x0058818A DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 17 0x0077575C DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 18 0x00777C20 DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 19 0x754A62FA gapfnScSendMessage - 0x00000000754A5FC8
2019-05-24 10:58:54 BF-1 20 0x754A6D3A GetThreadDesktop - 0x00000000754A6C63
2019-05-24 10:58:54 BF-1 21 0x754A6DED GetThreadDesktop - 0x00000000754A6C63
2019-05-24 10:58:54 BF-1 22 0x754A6E4C GetThreadDesktop - 0x00000000754A6C63
2019-05-24 10:58:54 BF-1 23 0x770B011A KiUserCallbackDispatcher - 0x00000000770B00EC
2019-05-24 10:58:54 BF-1 24 0x754A6A8C gapfnScSendMessage - 0x00000000754A5FC8
2019-05-24 10:58:54 BF-1 25 0x73747744 GetThemeBool - 0x0000000073746651
2019-05-24 10:58:54 BF-1 26 0x7374A092 SetWindowThemeAttribute - 0x0000000073749E39
2019-05-24 10:58:54 BF-1 27 0x73740B0D SetWindowThemeAttribute - 0x0000000073749E39
2019-05-24 10:58:54 BF-1 28 0x73740B96 SetWindowThemeAttribute - 0x0000000073749E39
2019-05-24 10:58:54 BF-1 29 0x754A72A2 GetPropW - 0x00000000754A722F
2019-05-24 10:58:54 BF-1 30 0x00777DEA GetPropW - 0x00000000754A722F
2019-05-24 10:58:54 BF-1 31 0x754A62FA gapfnScSendMessage - 0x00000000754A5FC8
2019-05-24 10:58:54 BF-1 32 0x754A731E GetDC - 0x00000000754A72CC
2019-05-24 10:58:54 BF-1 33 0x754A6DED GetThreadDesktop - 0x00000000754A6C63

2019-05-24 10:58:54 BF-1 34 0x754A6E4C GetThreadDesktop - 0x00000000754A6C63
2019-05-24 10:58:54 BF-1 35 0x770B011A KiUserCallbackDispatcher - 0x00000000770B00EC
2019-05-24 10:58:54 BF-1 36 0x754A6A8C gapfnScSendMessage - 0x00000000754A5FC8
2019-05-24 10:58:54 BF-1 37 0x73747744 GetThemeBool - 0x0000000073746651
2019-05-24 10:58:54 BF-1 38 0x73756E85 GetCurrentThemeName - 0x00000000737563AE
2019-05-24 10:58:54 BF-1 39 0x73740B0D GetCurrentThemeName - 0x00000000737563AE
2019-05-24 10:58:54 BF-1 40 0x73740B96 GetCurrentThemeName - 0x00000000737563AE

2019-05-24 10:58:54 BF-1 41 0x754A72A2 GetPropW - 0x00000000754A722F
2019-05-24 10:58:54 BF-1 42 0x00777DEA GetPropW - 0x00000000754A722F

2019-05-24 10:58:54 BF-1 43 0x754A62FA gapfnScSendMessage - 0x00000000754A5FC8
2019-05-24 10:58:54 BF-1 44 0x754A6D3A GetThreadDesktop - 0x00000000754A6C63
2019-05-24 10:58:54 BF-1 45 0x754A77D3 CharPrevW - 0x00000000754A7694
2019-05-24 10:58:54 BF-1 46 0x754A789A DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 47 0x007690A4 DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 48 0x00768F2D DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 49 0x00769024 DispatchMessageW - 0x00000000754A788B
2019-05-24 10:58:54 BF-1 50 0x008A03C8 DispatchMessageW - 0x00000000754A788B