My beardie Iroh is an adult, unknown age but not old. It’s been a while since I last weighed him as I got very sick. Anyway his last weights were all very consistent (see attached photos) but the one from today seems off. I checked it twice and both times same outcome. I checked because he seemed to have put on weight now that he is eating better but apparently not? He switched over to dubias in that time, started eating salads better due to Strawberry and Banana flavored calcium powder (amazing stuff). His belly is squishy now? I don’t understand. Be is a big boy, 23 inches last time I measured him.
Check the scale you are using. Make sure it's level. Put in fresh batteries. Tare the weight. For small kitchen scales checking the weight of a few coins is a fantastic way to check the accuracy. Just look up the weight of the coins you have against the US Mint or whatever country you are in and see if the scale can measure those accurately
Even the first 3 weights listed do not seem consistent for an adult dragon's weight. If he looks the same, based on the info you shared, I wonder if the scale is accurate. A scale having a bad battery or being out of calibration makes more sense to me than a beardie changing weight that much without any other sign of illness or appetite changes. Are you sure your scale is accurate?