Zealot's Oath + Eternal Life [Lich]

When using Zealot's Oath in combination with the Eternal Life (Lich) mechanic, my Energy Shield gets stuck at very low values (usually 1 or 2) and stops regenerating.

It appears to occur because when my Life is nearly full and Energy Shield is empty, my Life regeneration fills my Life completely, at which point the regeneration shifts to Energy Shield due to Zealot's Oath. However, since Eternal Life prevents any changes to Life once it is full, Life cannot fluctuate, causing the Energy Shield regeneration process to halt and remain stuck at extremely low values.

Is this a bug or something?

https://youtu.be/BkOhVJbZ7bQ