Jeremy Corbyn's indyref2 stance makes election "harder" for Scottish Labour - Kezia Dugdale
The mixed message may undermine a repeat of Labour's "sweetspot" campaign of 2017, Ms Dugdale said, which saw it capture six extra Scottish seats.
"The sweetspot in 2017 which delivered an increase in Labour MPs was being anti-independence and an anti-austerity," Ms Dugdale told the BBC's Sunday Politics Scotland.
"I think it's harder now for Labour in Scotland to make the case that they're the staunchest people against independence because of the UK message about conceding a second independence referendum.
She added: "Richard Leonard would much prefer to be talking about public services and austerity anyway, that's his natural strength, that's what he wants to do, so I think you'll see less of a focus on the threat of indyref2 and more of a focus on public services.
"The question is, is that what the electorate want to talk about or do they want to talk about the EU?"
Shadow Business Secretary Rebecca Long-Bailey again indicated today that Labour could allow a second vote on Scotland leaving the UK.
"We want Scotland to be part of Great Britain, we think that we're fantastic partners," she told Sky news' Sophy Ridge on Sunday.
"But ultimately what we have said is that after the next Scottish Government election, if the Scottish Government determine that they want to pursue another referendum and they go through the legislative process within their own Government to push that forward, as Government we wouldn't stand in their way, we wouldn't try and stop it.
"But we certainly wouldn't be campaigning to advocate that Scotland leaves the United Kingdom at all."