One potential conflict in terms of broadband for AYS in case of...

One potential conflict in terms of broadband for AYS in case of a takeover by Singtel/Optus could have been the fact that besides NBN they were also reselling TPG's (or rather their subsidiary's AAPT's) network in Sydney, Melbourne, Adelaide, Brisbane and Perth. 16 months before being acquired by AYS AusBBS made a corresponding announcement on 16 March 2015 (https://ausbbs.com.au/news/).

The fact that AYS in their  2018 full year results presentation (p 11, https://www.asx.com.au/asxpdf/20180827/pdf/43xpmtq3nbv34n.pdf) stated they had "implemented multiple carrier capability with launch of Optus and LBNCo network integration (in addition to AAPT)" sounds like most or all legacy customers from AusBSS were on TPG's/AAPT's infrastructure despite AusBBS had also been offering NBN products from as early as April 2012.

That actually again supports my suspicion that broadband was divested partly because a takeover would have caused legal issues for the broadband business as TPG/AAPT would probably have opposed their direct competitor to resell their network as much as Optus would not want to do that for commercial reasions.