2008 Jeep Wrangler X RHD Overheating

My jeep overheated the other day. Added coolant and seems better but Gauge seems to fluctuate with acceleration. I hadn’t noticed this before. Is this usual?

No it is not normal, any chance for a repair under warranty?

No, 45,000 miles. Also had a couple of episodes recently where the gauge pitched completely to the Cold side and stayed there. When turned off and returned to start vehicle it was back to “normal”.