Normal? A minor quirk? Or have I got a defective model?
Not normal - it's not the expected behaviour
It is more likely a quirk , being a one time occurrence , not noticed since nor on your previous device
What may have caused it?
Firstly, being a one off occurrence, it is non – reproducible ruling out further investigations to establish the reason. My best guess is this :
- From Andrew's answer , to a related question, the charging speed indication is
....based on power (in milliWatt) it receives. As shown on the commit log, "Charging speed based on voltage", from the same config.xml file,
<!-- Threshold in micro watts below which a charger is rated as "slow"; 1A @ 5V -->
<integer name="config_chargingSlowlyThreshold">5000000</integer>
<!-- Threshold in micro watts above which a charger is rated as "fast"; 1.5A @ 5V -->
<integer name="config_chargingFastThreshold">7500000</integer>
- Charging slowly: < 5W
- Charging: 5W - 7.5W
- Charging rapidly: > 7.5W
- In your case, the hesitation you refer to , indicates that power received by the device varied casuing it to fluctuate between Charging -stop- charging rapidly . This may have been caused by loose contact of the USB (on either end ), pocket lint or dirt preventing proper contact or power fluctuations at source ( voltage fluctuations ).
Edit: Note that that difference between Charging upper limit ( = 7.5 W ) and Charging rapidly ( > 7.5 W ) is borderline (unlike Charging slowly < 5 W), so intermittent poor connection or marginal fluctuation in input power is enough to have caused this
Next steps
You would need to pay attention to see if it happens again, which then would be a cause for concern as reported in Google forums - Pixel and Charging Problem and elsewhere on Internet. Solutions offered there have mixed results
If these solutions, don't help, my suggestion would be to change the cable and charger (see related question at bottom ) - simply because , they are more likely to fail rather than the device itself being the culprit ( probability wise , from experience and information on Internet)
Should this behaviour be a cause for worry? - No. Since it has not been observed since. If I were in your place, I would anyway buy, spare accessories , just to have peace of mind and use the current ones as back up (doesn't hurt to have spares) , especially it being a top end device.
Related How to select a Non OEM USB Type C charger or cable for my device?