Routes often truncated leaving just four points

FlightAware General
1

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
just

3800N/13000W ALLBE PASIF PIRAT2

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.

2

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