Does this CHEOPS first light image imply bad astronomy? @KeithMcClary's comment under lousy mirror corrected by software links to Bad Astronomy's First Light for the Exoplanet Hunter Mission CHEOPS Goes Tetrahedral which shows the image below.
I understand that in order to do precision photometry with a pixelated sensor one wants to spread the light over several pixels in a controlled way, but is this particular PSF the result of some painstaking optimization, some problem with the figure of one of the telescope's elements (oh no I hope it's not 1990 all over again!) or just because it's preliminary and they'll tweak something to make it more symmetrical?
If it stays this way, will it degrade CHEOPS' performance?

CHEOPS launched on 18 December, 2019, and on 07 February, 2020, it took its very first image of a star! The target chosen was HD 70843, a star about 155 light years away that’s a little bit hotter and brighter than the Sun.
The image, traditionally called First Light by astronomers, is itself … surprising.
As the article you reference makes clear, the defocusing is deliberate. It spreads the light of bright stars (the main targets for CHEOPS) over more pixels and hence mitigates saturation and non-linearity problems in the detectors.
The first light images look very similar to simulated pre-flight images (e.g. Hoyer et al. 2020; Futyan et al. 2020). The first light images are in line with expectations. There is therefore no unexpected problem with the telescope or optics, as there was with HST, and therefore no unexpected compromise of the mission sensitivity or goals.
From Hoyer et al.

The focal plane is defocussed to deliver a large PSF with a 12 pixels radius encircling 90% of the
flux. As a result of the combination of the Ritchey-Chrétien design and other specific features of the building of the telescope,
the PSF exhibits sharp and peaky features at sub-pixel level.

The reasons for the weird defocused PSF shape are discussed in section 11.1 of Benz et al. (2020). The triangular pattern is caused by strain on the primary mirror from a three-point fixation mechanism. This fixing mechanism was added to ensure that it wasn't shaken out of alignment during launch. In fact, Benz et al. say that the measured PSF (in zero gravity) is a little bit more symmetric, wider and smoother than found in the laboratory calibration tests. As a result there are some positives for observing bright stars - reducing the possibility of image saturation, but the situation is slightly worse for fainter stars because the wider PSF introduces more background signal into the photometry aperture.