It doesn't really have negative implications for MSRs in general. It's just one design out of many.
The debunked claim is just that they could get uranium fuel utilization comparable to a fast reactor, using a reactor operating mainly in the thermal spectrum. None of the other projects make that claim; either they actually are fast reactors (Moltex, Terrapower), they claim much lower fuel utilization (Terrestrial Energy), or they plan to run on thorium.
The debunked claim is just that they could get uranium fuel utilization comparable to a fast reactor, using a reactor operating mainly in the thermal spectrum. None of the other projects make that claim; either they actually are fast reactors (Moltex, Terrapower), they claim much lower fuel utilization (Terrestrial Energy), or they plan to run on thorium.