JFormMap functionality not working in VR

[Piranha91]

Apologies if this is a mistake on my end, but I've twice encountered an issue where a script I compiled is functional in SSE using JContainers SE , but not in VR using JContainers VR (both version 4.1.13). My latest instance of the issue is in a very simple script:

Scriptname SynthEBDHeadPartLoaderQuestScript extends Quest

import PSM_SynthEBD

GlobalVariable Property loadingCompleted Auto

Event OnInit()
	debug.Notification("HeadParts OnInit")
	LoadHeadPartDict("OnInit")
EndEvent

Function LoadHeadPartDict(string caller)
	loadingCompleted.SetValue(0)
	int assignmentDict = JValue_readFromFile("Data/SynthEBD/HeadPartDict.json")
	if (assignmentDict)
		debug.Trace("SynthEBD: HeadPart Dict Read")
	else
		debug.Trace("SynthEBD: Failed to read HeadPart Dict")
	endIf
	int count = 0
	int maxCount = JFormMap_count(assignmentDict)
	debug.Trace("SynthEBD: HeadPart Count = " + maxCount as string)
	;more functionality here, but irrelevant for the given issue
EndFunction

The supplied json file exists in both cases, and appears in its entirety as follows:

{
	"__metaInfo": {
		"typeName": "JFormMap"
	},
	"__formData|Skyrim.esm|0x13476": {
		"Hair": "__formData|Skyrim.esm|0x85DC8"
	}
}

The papyrus log from SSE says:

[06/05/2022 - 11:33:08PM] SynthEBD: HeadPart Dict Read
[06/05/2022 - 11:33:08PM] SynthEBD: HeadPart Count = 1

The papyrus log from VR says:

[06/05/2022 - 11:35:45PM] SynthEBD: HeadPart Dict Read
[06/05/2022 - 11:35:45PM] SynthEBD: HeadPart Count = 0

This seems to be identical to the issue I posted about on the SSE Nexus Page on March 27, just in a different context. Am I missing something about how JContainers works, or is the JFormMap functionality not working correctly in the VR build?