Dropping odds are happening due to various reasons, such as increased betting volume, missing or reappearance of influencing players, game suspected of being fixed, etc.
If you wish to be involved in betting on any fixtures, it is highly recommend that you firstly register and open player accounts with as many bookmakers as possible in order to increase the number of odds choices.
By doing this, one can monitor the real time odds updates and choose the highest value for a maximized return of investment and be also entitled to various bookmakers bonus schemes.