Not sure if it is just me but on BizHawk 1.11.6
I loaded this watch file
SystemID GBA
0328E0 w h 0 Combined WRAM
032928 w h 0 Combined WRAM
032970 w h 0 Combined WRAM
0329B8 w h 0 Combined WRAM
032A00 w h 0 Combined WRAM
0 S _ 1
01E610 w h 0 Combined WRAM
01E658 w h 0 Combined WRAM
01E6A0 w h 0 Combined WRAM
then pressed control R to reset the core. It then crashed and gave me this error:
System.AggregateException: One or more errors occurred. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at BizHawk.Client.Common.WatchList.<>c__DisplayClass4.<RefreshDomains>b__3(Watch watch)
at System.Threading.Tasks.Parallel.<>c__DisplayClass31_0`2.<ForEachWorker>b__0(Int32 i)
at System.Threading.Tasks.Parallel.<>c__DisplayClass17_0`1.<ForWorker>b__1()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.InnerInvokeWithArg(Task childTask)
at System.Threading.Tasks.Task.<>c__DisplayClass176_0.<ExecuteSelfReplicating>b__0(Object )
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at System.Threading.Tasks.Task.Wait()
at System.Threading.Tasks.Parallel.ForWorker[TLocal](Int32 fromInclusive, Int32 toExclusive, ParallelOptions parallelOptions, Action`1 body, Action`2 bodyWithState, Func`4 bodyWithLocal, Func`1 localInit, Action`1 localFinally)
at System.Threading.Tasks.Parallel.ForEachWorker[TSource,TLocal](IList`1 list, ParallelOptions parallelOptions, Action`1 body, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
at System.Threading.Tasks.Parallel.ForEachWorker[TSource,TLocal](IEnumerable`1 source, ParallelOptions parallelOptions, Action`1 body, Action`2 bodyWithState, Action`3 bodyWithStateAndIndex, Func`4 bodyWithStateAndLocal, Func`5 bodyWithEverything, Func`1 localInit, Action`1 localFinally)
at System.Threading.Tasks.Parallel.ForEach[TSource](IEnumerable`1 source, Action`1 body)
at BizHawk.Client.Common.WatchList.RefreshDomains(IMemoryDomains core)
at BizHawk.Client.EmuHawk.RamWatch.Restart()
at BizHawk.Client.EmuHawk.ToolManager.Restart()
at BizHawk.Client.EmuHawk.MainForm.LoadRom(String path, LoadRomArgs args)
at BizHawk.Client.EmuHawk.MainForm.RebootCore()
at BizHawk.Client.EmuHawk.MainForm.CheckHotkey(String trigger)
at BizHawk.Client.EmuHawk.MainForm.<ProcessInput>b__1d(Boolean current, String trigger)
at System.Linq.Enumerable.Aggregate[TSource,TAccumulate](IEnumerable`1 source, TAccumulate seed, Func`3 func)
at BizHawk.Client.EmuHawk.MainForm.ProcessInput()
at BizHawk.Client.EmuHawk.MainForm.ProgramRunLoop()
at BizHawk.Client.EmuHawk.Program.SubMain(String[] args)
---> (Inner Exception #0) System.NullReferenceException: Object reference not set to an instance of an object.
at BizHawk.Client.Common.WatchList.<>c__DisplayClass4.<RefreshDomains>b__3(Watch watch)
at System.Threading.Tasks.Parallel.<>c__DisplayClass31_0`2.<ForEachWorker>b__0(Int32 i)
at System.Threading.Tasks.Parallel.<>c__DisplayClass17_0`1.<ForWorker>b__1()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.InnerInvokeWithArg(Task childTask)
at System.Threading.Tasks.Task.<>c__DisplayClass176_0.<ExecuteSelfReplicating>b__0(Object )<---
I narrowed it down, and it seems to do this whenever I use a separator for the watch file. This is the mgba core, if it's relevant.