Routes often truncated leaving just four points

On IFR Route Analyzer ✈ Taiwan Taoyuan Int'l - San Francisco Int'l (RCTP-KSFO) - FlightAware
we can see that there is some error happening, causing
all but the final four items to be thrown away. Leaving for example


very often.

It cannot possibly be one airline to blame, as the same error happens a
certain percent of the time regardless of airline.

Also when it happens, it leave exactly four points. The first is
Lat/Lon, and the rest are waypoint names.

And on the map on

we see the ‘planned route’ dashed line has a big turn that reflects data
that is no longer anywhere on