After returning to his native country, he resumed his charge as minister and titular Bishop of Brechin, attending
general assemblies of the
Scottish Church in his capacity as bishop.
James Paton,
Bishop of Dunkeld, another Argyll acolyte, accused Caimbeul of giving out pensions on the revenues of his bishopric. This came before the Edinburgh assembly of March 1575, which ordered that John Erskine of Dun, Superintendent for
Angus and
the Mearns instruct Caimbeul on the duties befitting a bishop. Five years later, Bishop Alasdair was once again in trouble with the church. He failed to attend a summons issued to him by the
Dundee assembly of July 1580, and in 1582 another assembly ordered the Presbytery of the Mearns to bring charges against him. The outcome of these charges is, however, not known, as the records do not survive. In the following two decades, though, Caimbeul can be seen to take an active part in establishment politics, attending many assemblies, parliaments and meetings of the
privy council, often acting as a supporter of Argyll. Notably, the privy council which met at Brechin in April 1602 denounced him as a traitor, even though Caimbeul himself was sitting on it. That was the last time that Caimbeul sat on the privy council. ==Death and family==