Nested reference type record values and nullable constraints

Given the following examples I can’t quite figure out what the compiler is doing here.

type InnerRecord = { Id: int }

[<Struct>]
type StructRecord = { Value: obj }
// Ok
let nullable = Nullable({Value = 1 })

[<Struct>]
type StructRecord2 = { Value: InnerRecord }
// A generic construct requires that the type 'StructRecord2' have a public default constructor
let nullable = Nullable({Value = { Id = 1 }}) 

[<Struct>]
type StructType(value: obj) =
    member _.Value = value
// Ok
let nullable = Nullable(StructType(1))

[<Struct>]
type StructType2(value: InnerRecord) =
    member _.Value = value
// A generic construct requires that the type 'StructType2' have a public default constructor
let nullable = Nullable(StructType2({ Id = 1 })) 

[<Struct>]
type StructType3(value: StructType) =
    member _.Value = value
// Ok
let nullable = Nullable(StructType3(StructType()))

[<Struct>]
type InnerStructRecord = { Id: int }

[<Struct>]
type StructType4(value: InnerStructRecord) =
    member _.Value = value
// Ok
let nullable = Nullable(StructType4({ Id = 1 }))

Why specifically is it not allowed to store a struct that has a reference type record as one of its fields? (And then secondly, if it is expected behavior the error is supremely unhelpful in figuring this out)

This issue seems related to a previous issue https://github.com/dotnet/fsharp/issues/7946#issuecomment-687266672 but the linked explanation reads like it should only apply to generic structs.

[NinoFloris]

Workaround for now shows how busted the compiler behavior is here.

[<Struct>]
type Holder<'T> = Value of 'T
and 't holder = Holder<'t>

type InnerRecord = { Id: int }

[<Struct>]
type StructRecord2 = { Value: InnerRecord holder }
// Ok
let nullable = Nullable({Value = Holder.Value { Id = 1 }}) 

[dsyme]

@NinoFloris Thanks, I’ll take a look