George, you are right!
– Usually, I stay with AdobeRGB colour space and have set PS to rendering intent relative colorimetric, as I don’t like all colours being shifted to fit in. With printing, I almost always use softproof to correct black point and oversaturated colours if any, depending on the specific paper.
– The only time I convert to sRGB is for internet stuff, to exchange with people without wide gamut display and to send off pics, when ordering photobooks.
PL uses rendering intent perceptual for export → Add soft proofing to Photolab - #16 by sankos
(and further down). – So, it could have ‘solved’ this clipping. 
@Alexkon, thank you for your observation. Next time I’ll check for clipping, when I export to JPEG / sRGB.