The AirPod sometimes doesn’t charge

Hello,

Is this happening to both at the same time while the case still has a charge after they are removed? If so, there may be an issue with the software but if it's happening to one or either here and there it may just be from dirt or debris on the charging connections. Try wiping them down before putting them in the case, especially if this is happening more after wearing them during a workout.

Cleaning AirPods, AirPods Pro, AirPods Max, and EarPods - Apple Support

"Clean your AirPods and AirPods Pro

• Don’t run AirPods or AirPods Pro under water.
• Use a soft, dry, lint-free cloth.
• If your AirPods or AirPods Pro are exposed to anything that might cause stains or other damage—for example, soaps, shampoos, conditioners, lotions, perfumes, solvents, detergent, acids or acidic foods, insect repellent, sunscreen, oil, or hair dye:
  • Wipe them clean with a cloth slightly dampened with fresh water and dry with a soft, dry, lint-free cloth.
  • Allow them to completely dry before placing in the charging case.
  • Don't attempt to use them until they're completely dry.
• Make sure not to get any liquid in the openings.
• Clean the microphone and speaker meshes with a dry cotton swab.
• Don't use sharp objects or abrasive materials to clean your AirPods or AirPods Pro.

Clean the case of your AirPods or AirPods Pro

Clean the charging case with a soft, dry, lint-free cloth. If necessary, you can slightly dampen the cloth with isopropyl alcohol. Allow the charging case to dry. Make sure not to get any liquid in the charging ports. Here are a few more guidelines:

• Remove any debris from the Lightning connector with a clean, dry, soft-bristled brush.
• Don't use abrasive materials to clean the charging case.
• To avoid damaging the metal contacts, don't put anything in the charging ports.

Clean the ear tips of your AirPods Pro

1. If any water has accumulated in the ear tip, tap the AirPod on a soft, dry, lint-free cloth with the ear tip opening facing downward to remove.
2. Pull off the ear tips from each AirPod and rinse the ear tips with water. Don't use soap or other household cleaners.
3. Wipe the ear tips with a soft, dry, lint-free cloth. Make sure that the ear tips are completely dry before reattaching to each AirPod.
4. Click the ear tips back on each AirPod. The ear tips are oval shaped, so make sure that you align them before you click them back on."

I hope this helps.