The typesetter just used extra space before some of the commas to help get the text block properly justified on the right edge. So [space],[space] is completely equivalent to [no space],[space]. You should typeset without the space before the commas.
When interword spacing is used for justification, one of the longstanding standard principles in typesetting is that you want to avoid having the large white spaces in multiple (esp. 3 or more) successive lines of text line up in such a way that they form a noticeable path or 'river' down the page (rivers that run over just 2 lines can be quite hard to avoid, esp. in a text that has many short words); as I consider the occurrences of [space],[space] in the example, it looks to me that space is being used in front of the comma instead of an extra wide space after it precisely where this is necessary to prevent such rivers.
And I think this explanation really does apply to all instances of [space],[space] that are shown. Imagine that 'incidentes' in line 2 were followed by [no space],[large space]; in this case, there would be a strong diagonal river in the first 3 lines to the right of 'nos' – 'incidentes,' – 'non'. Likewise, imagine that 'videre' in line 3 and 'acquieverim' in the last line were followed by [no space],[large space]; in this case, there would be a 4-line river running to the right of 'videre,' – 'eminentia' – 'extollimur' – 'acquieverim,'.
Note also that, technically, there's a river at the beginning of lines 2–6 (to the right of 'nanos,' – 'plura' – 'visus' – 'altum' – 'Et'). In this case, though, all the spaces are regular size – or perhaps even a bit thinner – so the effect is mitigated and the alignment of spaces over 5 lines doesn't 'read' as a river.