BJP dumped TDP or let down by a mistake?

Reports are coming that the five invalid votes polled in MLC elections belong to BJP MLAs. It is learnt that BJP MLAs have given first preference to TDP candidate and second preference vote to NOTA.

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However according to rulebook, NOTA option in any preference after first preference will make the vote invalid. And so all the BJP votes were invalid. The sole Valid NOTA vote belongs to TDP’s defiant MLA R.Krishnaiah.

It is not yet known if BJP MLAs intentionally cast invalid vote or is it a mistake. Given BJP state unit not always favorable to alliance with TDP, their actions in this election are doubtful.