Ann: Half Year Results Presentation, page-7

James Gerrish, Livewire offers plausible explanation:

NXT +2.39%: the data centre operator was out with HY numbers today which look to be tracking well toward FY expectations. Revenue was a small miss, however, EBITDA at $77.5m was ~7% ahead of the market. Importantly, both active and contracted utilization was strong, showing the strength in demand. Revenue guidance was pushed to the higher end of the prior range, while EBTIDA guidance was maintained. The market was initially concerned about the large CAPEX increase, guiding to $620-670m, up $250m from the prior range. The investment comes on the back of brought-forward investment in a number of sites which is likely to bring in profit ahead of current expectations while the company still has $2b in available capital at the end of the half.