Mr Bongard was up for re-election as a director.
Results of the shareholder poll were 11.5 million votes for his re-election and 13.9 million votes against. But 31.1 million shares voting in favour were not counted because of a technicality regarding their proxy status.
THL chairman Keith Smith said the board was disappointed that with the majority of holders in favour of the resolution, a highly capable director had left the board.
Mr Bongard's details had been removed from the THL website yesterday.
Craigs Investment Partners broker Chris Timms said he had never heard of any other company that had managed to have a director voted off the board in such a manner.
"I'm not sure how it could have happened. Maybe there was something wrong with the form. I don't know how else they could get 28% of votes declared invalid.
"This is a major 'shoot yourself in the foot' moment," Mr Timms said.
THL chief executive Grant Webster was not available for comment.
In response to a shareholder's request, THL also issued an updated forecast trading result for the six months to December.
Earnings before interest and tax (ebit) would be in the range of $4.2 million to $5 million and an after-tax loss would be in the range of $1 million to $500,000.
That was down on the previous corresponding period's ebit of $11.5 million and after-tax profit of $4.2 million.
Chief financial officer Ian Lewington said the forecast reduction in ebit reflected the impact of the Rugby World Cup on the previous corresponding period's New Zealand rentals results, an estimated $4.5 million.
In addition, there were costs associated with the merger of the New Zealand rentals business with Kea Campers and United Campervans. Other impacts came from the change in accounting treatment for fleet rebates in the United States operation.