In PowerShell v6, Convert(To\From)-Json uses Newtonsoft.Json. ConvertTo-Json acknowledges JsonIgnoreAttributes but does not honor JsonPropertyAttributes. have some objects that are decorated with these attributes and serialize differently between ASP.NET and PowerShell. I've had to make a hacked version of ConvertTo-Json to support these attributes. For me, it results in a difference in casing which causes my JavaScript code to fail.
I propose that the JSON cmdlets honor the JsonPropertyAttributes placed on properties.