clickedObjectIDsAfterSearch gets 422 response: Invalid type for field events: expected string, got number

I am attempting to send a clickedObjectIDsAfterSearch click event to Algolia (I have sent other events successfully) and am receiviing a 422 error. I have tried this using JavaScript and PHP and get the same error. As far as I can tell I am coding this correctly as per The error returned says “Invalid type for field events: expected string, got number”.

When I go to the Events Debugger in the Algolia Dashboard and click the errored event this is what I see:

  "events": [
      "eventType": "click",
      "userToken": 20281,
      "index": "my_index_name_here",
      "eventName": "Dropdown: Product Clicked",
      "queryID": "acf55d7618e1e98922028e8dc7c43e11",
      "objectIDs": [
      "positions": [

So I can see why that error is returned. But as far as I can tell this is being coded correctly. I feel like I’m missing something obvious. If anyone can give me a pointer as to what I could be doing wrong that would be appreciated.

My array of objectIDs wasn’t cast as an array of strings - the error was confusing. Anyhow looks to be OK now.