Ok, I understand now, looking at the same trend in August as in July.
Was confusing bookings with Sales… so sales will be counted only when deliveries are going to happen which as you rightly pointed out will happen in October for Hero, but the declining trend for Bajaj(-31%) is worrisome given that deliveries may have already started Triumph Speed 400 Batch Out: Triumph Motorcycles rolls out first Speed 400 batch from Bajaj's Chakan plant: Deliveries to begin soon - Times of India
FY23 YTD July Sales were 24% higher than FY22 YTD July but FY23 YTD Aug sales are 21% higher! So growth continues but some impact due to potential postponement by potential Bajaj Triump/ Hero HD X440 buyers 