This was the first time it ever happened to me, and it only concerned the bonus Avios for a three-month promo they ran earlier this year. My Chase card statements itemized the Avios earned from regular activity, and the bonus Avios from the promo, however only the former were correctly credited to my BAEC account. Chase ran a few similar promos in the past few years and the bonus Avios were always credited correctly, so this was a one-off.