It's possible that the delay is due to lack of legal clearance in the customer country. Starlink needs to get approval to install and operate the ground station satellite links in each country. From the few authoritative statements I've seen those are sometimes delayed due to local country bureaucracy.
I ordered Starlink in the UK in February 2020 and the equipment finally arrived in May 2020. I /think/ the stated delivery estimate at the time was 2-3 months and never reduced until the order confirmation email arrived and I paid the balance, after which the equipment arrived a couple of weeks later.
For example, Starlink claimed in early 2021 to be launching in Viet Nam "within a year", and have been selling pre-orders, but they can't legally operate in VN unless they form a JV with a local partner, since foreign companies aren't allowed to provide telecoms services there. The relevant government agency went on record saying that Starlink hasn't even applied for permission, yet they're still selling pre-orders.
In your Viet Nam scenario and similar cases I wonder if it is (partially) a result of the Starlink plan to use direct satellite to satellite LASER links to relay data in low earth orbit to a more remote existing ground station?
As in, if I recall correctly, SpaceX originally expected to be launching 'block 2' satellites with LASER links in mid 2021 but suffered internal hidden delays (that led to Musk's internal SpaceX existential warning in October 2021 and firing of some senior staff) so the first batch were only recently launched in early 2022.
Those LASER links being in place are likely a prerequisite for serving territories where SpaceX cannot obtain favourable permissions for ground stations.