The edition of November 2016 had held (emphasis added):
If the department whose decision is contested considers the appeal to be admissible and well founded, it must rectify its decision. This does not apply where the appellant is opposed by another party to the proceedings.
The obligation or possibility of rectification may thus arise in connection with a decision by the Receiving Section, the Legal Division or an Examining Division. In opposition proceedings, it only arises in the special case that all the notices of opposition have been withdrawn and the proprietor of the patent files an appeal.
The last sentence in bold had been ommitted in the following editions, and the EPO had effectively changed the practice in this respect.
However, a recent BoA decision held that it amounts to a substantial procedural violation when interlocutory revison is not granted in such circumstances; see T 1558/18. Thus, the last sentence should be re-introduced into the Guidelines, and the practice be changed again.