It's not exactly the same problem, but it's still the entity tracker.
I uploaded the file:
https://www.replaymod.com/replay/11351
java.lang.IllegalArgumentException: NaN is not a valid double value as per JSON specification. To override this behavior, use GsonBuilder.serializeSpecialFloatingPointValues() method.
at com.google.gson.Gson.checkValidFloatingPoint(Gson.java:324)
at com.google.gson.Gson$2.write(Gson.java:292)
at com.google.gson.Gson$2.write(Gson.java:278)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:69)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:125)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:243)
at com.google.gson.internal.bind.ObjectTypeAdapter.write(ObjectTypeAdapter.java:107)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:69)
at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:208)
at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:145)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:69)
at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:208)
at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.write(MapTypeAdapterFactory.java:145)
at com.google.gson.Gson.toJson(Gson.java:669)
at com.google.gson.Gson.toJson(Gson.java:648)
at com.google.gson.Gson.toJson(Gson.java:623)
at com.replaymod.replaystudio.util.EntityPositionTracker.saveToCache(EntityPositionTracker.java:116)
at com.replaymod.replaystudio.util.EntityPositionTracker.load(EntityPositionTracker.java:92)
at com.replaymod.simplepathing.gui.GuiPathing.lambda$3(GuiPathing.java:502)
at com.replaymod.simplepathing.gui.GuiPathing$$Lambda$411/832168986.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)