I am completely lost on continuity of ownership tests, just want an explanation on how the following scenario is right? I don't understand.

At the start of the loss year the ownership was H (20%); L (45%) and D (35%). On 1/1/18 H sold his 20% to L and D equally which means that L had 55% and D 45%. This change of ownership does not cause a failure of COT as > 50% held by the same persons (L & D).

On 1/1/19 D sold his shares to L. only Ls original shares (45%) have been subject to the same ownership. COT is failed at this time as > 50% shares are not beneficially held by the same persons for the ownership test period.