My understand, perhaps incorrect, is that all support for Maple as the symbolic engine after R2010b was supplied by Maplesoft -- e.g., symengine cannot be set in current versions.
I confirm the integration oddity in Maple 15; later today I will test in a newer Maple version and will report a bug if it happens in that version as well.
I have a good idea of what the response will be probably be, though: that it is a boundary-condition issue. Definite integration works by extrapolating the function from s and s+deltas and taking the difference and working that back to expression form for the indefinite integral, and then substituting in the actual limits supplied; that algorithm is known to produce odd results when the behavior of the function changes significantly with increasing values.
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