According to all the sources cited in Why does OGO-1's trajectory and imminent reentry come from sky surveys and NEO tracking rather than normal satellite tracking? OGO-1 is in a highly elliptical orbit, and n2yo gives it a period of nearly 60 hours!
In this answer I explain that generally speaking an object in an elliptical orbit that slowly decays will first circularize before reentering, since each small delta-v at periapsis tends to lower the apoapsis.
But that's not what's happening here. n2yo gives it's TLE and this shows an eccentricity of over 0.91.
Question: Why will OGO-1 reenter from a highly elliptical orbit rather than circularize first? Is there a rule-of-thumb to gauge which orbits will circularize before reentry, and which won't?
1 879U 64054A 20233.75378097 -.00000811 00000-0 00000+0 0 9999 2 879 54.9668 307.2269 9131889 205.8880 32.8586 0.40281857 21812