I don't know what's the suggested tyre pressure for R-Line but my SE Nav has 38psi all tyres when driven alone and 38 front / 41 rear with full load.
Therefore I suggest to check the sticker on the driver's door pillar because 33 seems too low to me. It would be comfier but I imagine 20" low profile R-Line tyres would be shot very quickly when under-pressured like this.
Occasionally, I find my TPM reporting low pressure only to find that the load mode has changed to Fully Loaded. I change it back to standard and it is back to close enough to the target pressure that it reports all is OK again. Not sure why it changed by itself but it's done it twice now and I wonder if it has something to do with the driving mode