The possible causes of your problem can be grouped by likelihood into three categories.
MOST LIKELY
Loose Wire. As @Steve Wellens indicated, a wire is not securely attached and operating intermittently.
Mode Misunderstanding. I often see people who assume they are in Hold mode when they are in Program mode.
Programmable thermostats have two primary running modes: Program and Hold. Program mode bases target temperature on a user programmable schedule and is typically invoked through some variation of “Run”, “Run Schedule”, etc. Hold mode overrides Program mode for manually setting target temperature. Most Hold modes are permanent, some are temporary and usually indicated by “Temporary Hold” in the display.
I see the “Hold” indicator on the thermostat but I don’t know if Hold mode was engaged when you went to sleep.
MODERATELY LIKELY
Bad thermostat. Intermittent thermostat problems are relatively rare, when a thermostat doesn’t work, it usually never works. However, it happens.
LEAST LIKELY
Weak batteries. If weak, your display probably wouldn't work and/or a low battery indicator would come on.
Weak mount. Though a poorly mounted thermostat will absorb some button pressing forces, I doubt it caused you to wake up to 63 degrees when your target was 67. That being said, your thermostat SHOULD be mounted solidly.
CONCLUSION
If you want to take your thermostat apart and troubleshoot yourself, or have a friend that can do so, please say so, and we can take it one step at a time. If you want to hire someone to solve the problem, a competent handyman or HVAC company can probably solve this.
