L515 sometimes displays consistent offset in depth values

Currently we are using a RealSense L515 mounted at a fixed point, aimed vertically downwards at a flat, matte gray surface, and have sometimes observed incorrect depth values from the camera, underestimating the depth value by as much as 4-5cm at ranges just under 1m. The camera appears to be operating in two modes: it either gives a correct depth value, with up to about 3mm of noise variation in the depth measurement, or gives an underestimated depth value also with about 3mm of noise variation in depth. The incorrect depth values are given by the camera for several minutes or longer at a time, and the underestimated depth applies to all depth readings taken while it is occurring (both the flat surface mentioned above as well as objects placed on this surface). Sometimes during operation, after several minutes of giving output centered at one set of depth values, the camera will shift over the course of about 5-10 seconds from underestimating the depth to more correct values, or vice-versa. There does not appear to be any clear pattern to how long it takes before this occurs.

We have tried the short range and low ambient light camera presets and observed no difference in this behavior (the camera setup is under generally indoor lighting conditions with a low possibility of incident sunlight at limited angles through an opaque skylight). For some time we thought the issue was related to the physical connection between the camera and computer, as removing and replugging the camera sometimes seemed to switch the camera from incorrect to correct behavior, but this does not seem to consistently be the case either. The camera is usually initially incorrect.

How can this error be fixed? In our use case when the camera is displaying the incorrect depth values they are offset by a sufficient amount that it makes the camera functionally unusable.