TarasD
Thank you for reporting this issue!

I can confirm that "Fleuve St-Laurent" appears over land (in Beaconsfield) when the map is viewed at zoom levels 13 and 14.

I admit I don't know why this is happening but there are invisible boundaries (recorded in OpenStreetMap but not displayed on the map) that may be causing the river's label to appear on land.

The island of Montreal is defined as "Île de Montréal" using an invisible boundary line. I can see this boundary line runs right through Beaconsfield, notably through the intersection of Windemere and Arlington (just below where "Fleuve St-Laurent" appears).

I admit I have no idea why this Island boundary line runs inland through several West Island communities! In addition, there's another invisible boundary line that defines Lac St-Louis and it also located inland, running through Beaconsfield south of Hwy 20. They may be coarse representations that need refinement or they simply serve as basic outlines that need no adjustment.

I hesitate to make any changes to these invisible boundaries because I'm not certain of their purpose and they may have nothing to do with the misplacement of "Fleuve St-Laurent".

A more proficient map-editor will have to examine this problem in greater depth.