Planet F1 reporting the Porsche - Redbull Deal is "dead" after the disagreement over control of the team:
Red Bull-Porsche deal ‘dead’ as parties fight for control of the team
Reports that Porsche were annoyed that Audi steamed ahead at Spa and confirmed their involvement too.
If this is true then it probably makes sense for them just to re-connect with Honda although I know that they've had concerns about being treated as a "new" engine manufacturer if Red Bull Powertrains are developing and building the engine and Honda just buy the naming given they already support the current engine.