Inconsistent behaviour of "paket outdated" depending on selected group

[markpattison]

Description

Running paket outdated -g Main for the main dependency group returns No outdated packages found.

Running paket outdated returns some updates for the same dependency group (which is correct):

Outdated packages found:
  Group: Main
    * FSharp.Core 5.0 -> 5.0.1
    * Microsoft.NETCore.Platforms 5.0 -> 5.0.2

Using paket version 6.0.0-rc002.

Repro steps

See this version of the affected repo:

https://github.com/markpattison/cubes/tree/af6ba5dacce5110a702764984d1ad4ea3df7b266

Expected behavior

Consistent results for paket outdated -g Main and paket outdated.

Actual behavior

Results are inconsistent

Known workarounds

Just run paket outdated, but this is a lot slower (>2 minutes against 12 seconds).