Should the lights blink on and off forever while charging at max?

Hi, I recently purchased a new Anker PowerCore Speed 20000 PD from here:

I have a few concerns about its behavior. After receiving the device yesterday, the first thing I did was set it charging using the included usb-c cable and wall charger. All seemed normal, as the lights changed from blinking to stable, starting from the first light toward the fourth and final light. However, after reaching the 3 stable, 1 blinking state, it seems to have started a kind of loop and I can’t figure out if this is normal from reading online.

With only the charging cable connected, it loops like this:

  1. 3 stable, 1 blinking for 2-10 seconds
  2. all 4 stable for 5-15 seconds (this step is sometimes skipped)
  3. all lights turn off for 15-30 seconds
  4. loop back to #1

In other words, the lights never stay off permanently after it seemingly has a full charge and it’s been looping like this for over 10 hours now. I’m not sure if this is normal or if the battery is defective or otherwise unable to hold its max charge state for more than 30 seconds, despite being plugged in.

To summarize my questions:

  1. Should the lights blink in a loop as described above while charging at max?
  2. Is it normal for there to be a faint pop-like sound each time the usb-c cable is detached from the device while it’s charging with the wall charger?
  3. Is it normal that the included usb-c cable was bound with a black rubber band, while the micro-usb cable was bound with a black twist-tie? Could it be that Amazon sent a defective return/refurb as new? I’m afraid of getting into a refurb cycle by contacting them, where they initially send a refurb as new and only replace it with other refurbs, so you never actually get the new product you originally ordered.

I’d appreciate any information about these questions and concerns.
Thank you for reading.

After checking some unboxing videos, it seems #3 is probably normal (usb-c has a rubber band, micro-usb has a twist-tie), so hopefully that’s fine. However, I’m still not sure about #1 and #2.

Is there anyone with a PowerCore Speed 20000 PD who knows if the 4 lights should stay off permanently after reaching full charge while plugged in or if the blink loop mentioned above is normal?

I noticed that the wall charger has a light that pulses even when it’s not plugged in to a wall socket. Could the issue here be that, even while plugged in, the wall charger drains the pb to power this light, so after charging stops (all lights turn off on the pb, while the wall charger light remains stable), it eventually needs to begin recharging again to offset the wall charger drain?

Anyone at Anker know if this is normal for the PowerCore Speed 20000 PD?