I understand Chinguetti's problems to be down to the reservoir being more complex and compartmentalised than believed when it was authorised, so pressure falls off faster and each well, particularly in certain areas, does not drain as many barrels as predicted. If partners have a policy to keep the reserves, then you have to keep drilling wells, which in today's environment is expensive.
Strategy-wise, TLW were already in Mauritania on other blocks, so they must see it as a core area. I don't think they would try to extricate themselves by selling off Chinguetti. Besides, there may be tariff income in the future if other smaller discoveries that can't currently justify dedicated infrastructure can be tied back to the Chinguetti FPSO.
But I'd appreciate a steer from any of the legacy-HNR folk who've migrated over here.