R1D2 wrote

Where did you read this? Last firmware for this AP increases the internal storage for associated clients to 64 at max., but this does only mean that storage capacity has been increased, not necessarily that 64 stations can connect to the AP simultaneously.

The practical limit of associated stations depends on many factors such as the client's usage pattern, WiFi mode and speed in use (dynamically negotiated!), available AirTime in this frequency band, interferences and many other environmental influences. Since the 2.4 GHz is often overcrowded, there is only a small amount of AirTIme stations can use to allocate a given channel. In real life you could connect between 15 to 25 stations to a 2.4GHz device using moderate bandwidth and maybe some more with small bandwidth usage if (and only if) you have an ideal WiFi environment, i.e. almost free WiFi channel, N mode used by all stations, 40MHz channel width (8 channels in use!) and excellent wireless link quality.

Furthermore, dropping connections may be caused by bad wireless links, for example on weak TX power etc. An indicator for this would be if the stations whose connections are dropped are always the same stations.