Hey Drbfrog,
Thanks for following up.
Is the display you are trying to connect using HDMI, or USB-C?
If USB-C, make sure the cable you are using is capable of supporting high definition video. We will link to two compatible cables on the Apple Online Store. You would also be able to use this cable to connect directly to a USB-C based display, but we understand you are trying to utilize this dock for multitasking and additional functionalities.
If using an HDMI display connection, ensure you are using a HDMI 2.0 cable, and consider testing another cable as well. A multi-port adapter is available from Apple which allows charging and video connection simultaneously. This may be a good addition to the setup or as an alternative way to connect. Some accessories are unable to charge the device and display video simultaneously, so this may be what is occurring. We will link to the AV Multiport Adapter below.
USB-C Digital AV Multiport Adapter
The link below will summarize the various ways to connect an iPad to a display with a cable.
Connect iPad to a display with a cable
You may also benefit from opening a support ticket with Lenovo or utilizing their community forums as well.
Lenovo Support
Lenovo Community
Thanks for using Apple Support Communities. Best wishes!