Air Carrier pilot reported autopilot changed from VNAV to Control Wheel Pitch and increased their descent rate; descending below the published crossing altitude at CRCUS on the ANGLL4 RNAV Arrival to LAX. The reporter stated the same issue occurred with the preceding aircraft on the same STAR.

Narrative

Approaching the CRCUS fix; the aircraft suddenly began a rather aggressive descent of over 4;000 fpm. Crew recognized and noted this. The aircraft was showing on path with no other anomalies noted which raised some confusion with the Crew as the aircraft was not showing off path or high. The closer we got to the fix we realized the aircraft was going to go below the 12;000 [ft.] MSL limit at CRCUS. At about the time the F/O (First Officer) began to intervene; the aircraft disconnected VNAV and went into control wheel pitch mode. VNAV Disconnect was not displayed in the scratchpad and no other indications were noted; it simply reverted modes unannounced and without warning. The F/O corrected the rate of descent smoothly; which led to a 300 [ft.] low excursion over CRCUS. The altitude was quickly corrected and the flight proceeded normally. ATC did call and ask about the deviation. We responded and explained the anomaly; no separation problems were noted and ATC did not seem to concerned. As an important note. The aircraft ahead of us was (other carrier) Aircraft Y [Same Aircraft Model]. When he heard our situation; he also communicated to ATC that the exact same thing happened to them. Their VNAV erroneously disconnected over CRCUS and they were forced to intervene with Vertical Speed mode.It appears due to two aircraft experiencing the same problem at the same time there may be a programming or database problem near CRCUS.