LEDs with Diodes in Parallel

Its not as easy to speculate without seeing a circuit schematic, and also learning more about the specific application or intention for the LED light strip. If I had to guess, it may be part of a reverse polarity protection circuit. This may be useful if someone accidentally switches the negative and positive wire leads going into the LED board. Also, it might provide the same function to the lower half of an AC waveform, if the LED board was designed to accept DC as well as AC inputs. Yet another possibility might include a function found on some LED taillights. If the LED board contains two power inputs to corresponds with various intensity modes (such as brake and taillights) and the circuit shares a common ground, then the diodes would be required to block current from flowing back into the automotive lines from the opposing power wire.