House prices are "lacking genuine direction", according to the Halifax, as it reported a 0.5% fall in values in September compared with August.
Prices were down 2.3% from a year ago, leaving the average home in the UK worth £161,132, the lender said.
It said there had been a mixed pattern of monthly changes in prices, but broad stability overall.
And the lender said it expected little change in prices and activity during the rest of the year.
"Greater uncertainty about economic and personal financial circumstances, together with pressure on householders' finances from weak earnings growth, higher inflation and increases in taxes, are likely to be constraining housing demand," said Halifax housing economist Martin Ellis.
"Despite these pressures, low interest rates and a rise in employment over the past year, have been supporting the market."
Prices in the three months to September were 0.1% higher than the previous three months.
The report of static house prices from the Halifax's lending data chimes with the latest figures from the Nationwide. The building society said last week that prices were "treading water".
However, the latest statistics on mortgage approvals from the Bank of England may suggest that sales funded by mortgage borrowing could pick up this autumn.
It said the number of new mortgages approved, but not yet lent, for home buyers rose to 52,410 in August - its highest monthly level since December 2009.
The monthly picture so far this year from the Halifax is one of with four rises, four falls and one month of no change in prices.
However, Alex King, from mortgage broker SPF Private Clients, said the picture could be different in local areas.
"An over-reliance on national data, such as that provided by the Halifax, masks the huge regional disparity in the UK market," he said.
"Within a matter of miles you can have two entirely different property markets - one fairly robust, the other in reverse."
Recent data from the Land Registry showed that prices in London had risen by 2.1% in the year to August, compared with a 7.8% fall in the north-east of England.