The British Army is carrying out a joint investigation with the manufacturer of the Ajax vehicles after trials were "paused as a precautionary measure".
The new vehicles, formerly known as the Scout SV (Specialist Vehicle), are being developed as part of a £4.5 billion deal with General Dynamics.
However, the Ministry of Defence's "expected cost to completion at approval" for the programme in 2019 was just under £5.5 billion.
In response to reports that noise and vibrations had impacted trials, the Ministry of Defence (MOD) said: "Some training on the Ajax family of vehicles was paused as a precautionary measure.
"This is a normal measure for the demonstration phase of projects; an investigation, incorporating trials, is being carried out jointly with the manufacturer.
"It is inappropriate for us to comment further at this time.
"The health and safety of our personnel is of the utmost importance and we are committed to providing a safe working environment."
The MOD added that additional checks to the platform are a "normal measure for the demonstration phase of projects", and that training on the Ajax variants has since recommenced.
Plans remain for the vehicles to be given initial operating capability in the coming months.
Six variants of the vehicle had been due to enter service in 2020.
Ajax will be a fully digitised, tracked, medium-weight core of the British Army's deployable intelligence, surveillance, target acquisition and recognition (ISTAR) capability.
The contract with General Dynamics was agreed to ensure 589 Ajax vehicles are delivered to the British Army across six variants.
A seventh variant, Overwatch, has since been announced.
To date, 14 Ajax vehicles have been delivered to the MOD, including the Ares variant, which is designed for reconnaissance and troop-carrying.
The first vehicles were delivered from Merthyr Tydfil, South Wales in February 2019, with deliveries continuing until 2025.
The Ajax programme aims to form a key component in the Army's modernised warfighting division, with current plans for Initial Operating Capability scheduled for this summer.
Defence Secretary Ben Wallace said Third Division will "remain the heart" of the UK's warfighting capability, leading NATO with two modernised heavy brigades.
This will be built around "a modern armoured nucleus" of vehicles, including the Ajax armoured reconnaissance vehicles.
Cover image: The Ares is set to replace the Army's Combat Vehicle Reconnaissance (Tracked) [CVR(T)] vehicles (Picture: British Army).