Unlike in 11 previous months, the Scottish Government failed to produce new figures at the end of last month on the sums collected by Land and Buildings Transaction Tax.
It means it has avoided having to admit that revenues for the tax have fallen short of original estimates - leaving a multi-million pound black hole in Scotland's finances.
Estimates suggest that the Scottish Government will fall short by between £38m and £42m on its original claim that £235m would be collected by the new tax.
The Scottish Conservatives warned repeatedly of the damage the SNP's plans could do.
The SNP's failure to publish figures comes after it also failed to publicise its deal with two leading Chinese firms ahead of the election.
Scottish Conservative leader Ruth Davidson said:
"The SNP's approach in this election campaign has been to bury bad news and spin its way back into office. It is the action of an arrogant governing party which has spent too long in power."
"These figures were published regularly at the end of each month for the last eleven months. Why suddenly the silence now?"
"We know the SNP tried to hide the truth over its negotiations with Chinese firms. Now we discover that information on its failed house-buying tax is missing. Voters are entitled to draw the conclusion that this is a party which is trying to run away from any inconvenient truths.”
"Our own calculations suggest that the SNP's black hole is between £38m and £42m. If the SNP wants to challenge that then it knows how - stop hiding the facts, and publish the truth."