diff --git a/regex/matching.go b/regex/matching.go
index dab6446..d2925bd 100644
--- a/regex/matching.go
+++ b/regex/matching.go
@@ -251,35 +251,39 @@ func (regex Reg) FindAllSubmatch(str string) []Match {
 	return indices
 }
 
-func addStateToList(idx int, list []nfaState, state nfaState, threadGroups []Group) []nfaState {
+func addStateToList(str []rune, idx int, list []nfaState, state nfaState, threadGroups []Group) []nfaState {
 	if stateExists(list, state) {
 		return list
 	}
 	if state.isKleene || state.isQuestion {
 		copyThread(state.splitState, state)
-		list = addStateToList(idx, list, *state.splitState, threadGroups)
+		list = addStateToList(str, idx, list, *state.splitState, threadGroups)
 		copyThread(state.next, state)
-		list = addStateToList(idx, list, *state.next, threadGroups)
+		list = addStateToList(str, idx, list, *state.next, threadGroups)
 		return list
 	}
 	if state.isAlternation {
 		copyThread(state.next, state)
-		list = addStateToList(idx, list, *state.next, threadGroups)
+		list = addStateToList(str, idx, list, *state.next, threadGroups)
 		copyThread(state.splitState, state)
-		list = addStateToList(idx, list, *state.splitState, threadGroups)
+		list = addStateToList(str, idx, list, *state.splitState, threadGroups)
 		return list
 	}
-
 	state.threadGroups = append([]Group{}, threadGroups...)
+	if state.assert != noneAssert {
+		if state.checkAssertion(str, idx) {
+			copyThread(state.next, state)
+			return append(list, addStateToList(str, idx, list, *state.next, state.threadGroups)...)
+		}
+	}
 	if state.groupBegin {
 		state.threadGroups[state.groupNum].StartIdx = idx
-		return append(list, addStateToList(idx, list, *state.next, state.threadGroups)...)
+		return append(list, addStateToList(str, idx, list, *state.next, state.threadGroups)...)
 	}
 	if state.groupEnd {
 		state.threadGroups[state.groupNum].EndIdx = idx
-		return append(list, addStateToList(idx, list, *state.next, state.threadGroups)...)
+		return append(list, addStateToList(str, idx, list, *state.next, state.threadGroups)...)
 	}
-	state.threadGroups = append([]Group{}, threadGroups...)
 	return append(list, state)
 
 }
@@ -340,7 +344,7 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
 
 	start.threadGroups = newMatch(numGroups + 1)
 	start.threadGroups[0].StartIdx = i
-	currentStates = addStateToList(i, currentStates, *start, start.threadGroups)
+	currentStates = addStateToList(str, i, currentStates, *start, start.threadGroups)
 	var match Match = nil
 	//	var isEmptyAndNoAssertion bool
 	// Main loop
@@ -362,7 +366,7 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
 				break
 			} else if !currentState.isAlternation && !currentState.isKleene && !currentState.isQuestion && !currentState.groupBegin && !currentState.groupEnd { // Normal character or assertion
 				if currentState.contentContains(str, idx) {
-					nextStates = addStateToList(idx+1, nextStates, *currentState.next, currentState.threadGroups)
+					nextStates = addStateToList(str, idx+1, nextStates, *currentState.next, currentState.threadGroups)
 				}
 			}