Thanks for asking.
These are different Quaker Monthly Meetings, for different time periods, and having two categories is correct. There is an explanation in the Monthly Meeting section of https://www.wikitree.com/wiki/Space:Quakers_in_Lincolnshire. Up to 1834 Broughton and Gainsborough had separate monthly meetings; from 1834 to 1871 they were amalgamated into Broughton and Gainsborough Monthly Meeting; from 1872 to 1920 they were separate Monthly Meetings again. So we need the separate categories. This sort of thing is common with Quaker English Monthly Meetings.
Almost all English Quaker Monthly Meetings covered an area - they were not limited to a particular town or village. So there are generally no specific geographical co-ordinates for them. The name given to them does not mean that they were based in the place which gave the name. The Monthly Meetings were commonly perambulatory: they commonly convened at the various local Quaker Meeting Houses in the area covered by the Monthly Meeting. I would not see the absence of co-ordinates as in any way an error, and to include co-ordinates would be misleading. If you want a comparison, look at the categories for ecclesiastical dioceses, which give no geographical co-ordinates. See as an example https://www.wikitree.com/wiki/Category:Diocese_of_Lincoln%2C_Church_of_England_Priests. This is true of dioceses even though, unlike most Quaker Monthly Meetings, they were "centred" on a particular place - the cathedral city.
If the absence of co-ordinates is giving rise to database suggestions, these are suggestions, not indications of definite errors, and can be marked as false.
If you have any further questions or doubts, please message me. Thanks. Michael Cayley, co-Leader, Quakers Project
[corrected for typos]