Miniprofiler crashing site: Index was outside the bounds of the array.

A background task in Umbraco seems to have triggered Miniprofiler except instead it threw the following error causing the site to error:

Umbraco.Core.Persistence.UmbracoDatabase - Exception.
System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at System.Collections.Generic.List`1.Add(T item)
   at StackExchange.Profiling.Timing.AddSqlTiming(SqlTiming sqlTiming) in c:\Code\github\SamSaffron\MiniProfiler\StackExchange.Profiling\Timing.cs:line 364
   at StackExchange.Profiling.MiniProfiler.AddSqlTiming(SqlTiming stats) in c:\Code\github\SamSaffron\MiniProfiler\StackExchange.Profiling\MiniProfiler.IDbProfiler.cs:line 101
   at StackExchange.Profiling.SqlTiming..ctor(IDbCommand command, ExecuteType type, MiniProfiler profiler) in c:\Code\github\SamSaffron\MiniProfiler\StackExchange.Profiling\SqlTiming.cs:line 72
   at StackExchange.Profiling.SqlProfiler.ExecuteStartImpl(IDbCommand command, ExecuteType type) in c:\Code\github\SamSaffron\MiniProfiler\StackExchange.Profiling\SqlProfiler.cs:line 53
   at StackExchange.Profiling.MiniProfiler.StackExchange.Profiling.Data.IDbProfiler.ExecuteStart(IDbCommand profiledDbCommand, ExecuteType executeType) in c:\Code\github\SamSaffron\MiniProfiler\StackExchange.Profiling\MiniProfiler.IDbProfiler.cs:line 117
   at StackExchange.Profiling.Data.ProfiledDbCommand.ExecuteDbDataReader(CommandBehavior behavior) in c:\Code\github\SamSaffron\MiniProfiler\StackExchange.Profiling\Data\ProfiledDbCommand.cs:line 239
   at Umbraco.Core.Persistence.PetaPocoCommandExtensions.<>c__DisplayClass5_0.<ExecuteReaderWithRetry>b__0()
   at Umbraco.Core.Persistence.FaultHandling.RetryPolicy.ExecuteAction[TResult](Func`1 func)
   at Umbraco.Core.Persistence.Database.<Query>d__74`1.MoveNext()

I'm not sure what triggered it but it 'resolved' itself after it timed out. Debugging is turned off. Anyone know what's causing this?

This is on Umbraco version 7.15.3