TPS65233 LNB Circuit is drawing more current from supply
What you seeing is probably the startup transient for charging the capacitors. It is possible that the input is starving and the regulator goes out of its operational parameters. Check with a scope the voltage on the chip input pin, if you see some oscillation this is the problem.
Also, have you checked with some load (even a simple resistor) attached? many regulators have issues without load since it's needed for stability.
If this doesn't help you should ask on the TI E2E forum posting your circuit layout, the TPS switchers are really sensitive to that, in my experience. The recommended layout in the datasheets is usually something like ``do it this way or it doesn't work'' if you haven't experience with the part.