  The origin of 3He abundance enhancements in coronal mass ejection
(CME)-driven shock gradual solar energetic particle (SEP) events remains
largely unexplained. Two mechanisms have been suggested - the re-acceleration
of remnant flare material in interplanetary space and concomitant activity in
the corona. We explore the first gradual SEP event with enhanced 3He abundance
observed by Solar Orbiter. The event started on 2020 November 24 and was
associated with a relatively fast halo CME. During the event, the spacecraft
was at 0.9 au from the Sun. The event averaged 3He/4He abundance ratio is 24
times higher than the coronal or solar wind value, and the 3He intensity had
timing similar to other species. We inspected available imaging, radio
observations, and spacecraft magnetic connection to the CME source. It appears
the most probable cause of the enhanced 3He abundance are residual 3He ions
remaining from a preceding long period of 3He-rich SEPs on 2020 November 17-23.
