I am running this simple query on an Amazon Neptune DB:

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": "100"     
} 

But I get the following error as a response:

  "detailedMessage": "Operation terminated (internal error)",
  "code": "InternalFailureException",
  "message": "Operation terminated (internal error)"

What gives?

I have tried other examples setting test to different values. All of them worked, which makes the problem even stranger. See these below:

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": "1"     
} 

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": true     
} 

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": false    
} 

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": 1    
} 

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": 100     
} 

{     
"query":"MERGE (t:Test {reference: $reference}) SET t.test=$test RETURN t",     
"parameters": {         
   "reference": "test",         
   "test": "test"    
}