Firstly, the Tamil channel is awesome,
was a stand out every morning! :-D
I had the same thing, but only when I had SRF3 as memory slot number 1.
I've now moved it to the 2nd memory location and am sticking with the 2nd memory location.
It works there, without constant searching and Tamil music.
Hope that helps.

Hello
No idea, the device is no longer in use.
Greetings

Is it possible that the entire radio is resetting itself?
Change something in the equaliser and check whether these settings are still saved next time.
Otherwise there is something wrong with the connected permanent positive. Voltage connections connected the wrong way round

I cannot reproduce this.

I can offer the following consideration:

Since you are talking about a Tamil station:
Your device is designed for DAB+ by air reception.
Is the antenna you used a DAB+ antenna for air reception or did you use the cable of a supplier (Sunrise, UPC, etc...) as an antenna? For radio via cable from a supplier, the DAB+ standard is not identical to the DAB+ transmitted by certain suppliers, it is then called 'DAB+ Cable' (more on this here, for example: https://www.upc.ch/de...).
If you have used a supplier's cable as an antenna, this is a possible cause.

There are various types of DAB+ aerials for aerial reception, including on this site.