The DVR is behaving as designed - splitting on silence.
The best option is to turn off "Split on silence" and manually set a recording duration (taking into account the duration of potential ads).
Turn off Splitting:  Settings tab > DVR tab, Split on Silence switch.
Setting a Duration:  Open the DVR browser and set the duration before recording
Alternatively you can recombine the split files: On the Home tab, select the files to combine in the list view and then from the menu select Combine.