The people who owned DL were paid in POET shares to buy DL. DL as an entity doesn't own any POET shares.
And even if that were no it the case, the $10m worth of shares that were used to purchase DL were valued at $1 each, so roughly 10m shares total. With POETs outstanding share count at ~285m the 10m shares used to purchase DL do not come close to the 10% threshold for reporting as a significant shareholder.