I checked the link you have provided which talks about BSE instruments. But I am fetching only NSE instruments. Below are instruments and number of times their fetch failed today with respect to timeframes (5min, 60min, day).
5minute
Instrument…
This is specific to history API only. With timeout as 5 sec, it seems to be working fine. But when it is lower, it times out sporadically, not specific to any trade symbol.