While its true, the main problem is bad pool software AFAIK. SPV mining is meant for the time while the pool software verifies the last block and builds a new block with possible transactions to include. This takes time and during that time miners have no work to do. Since miners that have nothing to do are a waste of money, they mine on an unverified and empty block. The main issue for orphans is the time it takes for a block you found to reach other miners. If two pools find a block at the same time, the block that reaches 50% of the networks hashrate first will win the race.