x-axis shows fractal milliseconds instead minutes and seconds (when using docker container)

By using docker and setting up a server by my own, I get a running system (GREAT work, thanks!)

However, instead of getting minutes and seconds on the x-axis (e.g. 1m 40.0 s) when using plot.ardupilot.org, I get a fractal number (e.g. 427518.324356435).

In Plotly.vue, the format is defined as: timeformat = ':02,2f'
But I cannot see, how the desired format is generated from that :-/

Examples below.

Good:

Worst:

Start by reproducing the x-axis output with the Docker-based server and a plot at plot.ardupilot.org. Inspect the timeformat setting in Plotly.vue, compare the displayed value with the desired minutes-and-seconds examples, and verify that the axis shows the intended format after the change.

Written by the indexing model from the issue text.