Not sure if this applies, but on the older cars the yellow indicator will not shut off if the replacement bulb is not the exact correct wattage.
I had replaced a brake light bulb on my 126 once with a regular 12V.
After tearing my hair out for several days , someone here had me look into the wattage thing. Sure enough the new bulb was 12V10watts and the car demanded 12V20watts. The trunk issue does correspond to what I suggest.
Good Luck