If you look to the datasheets of the Seiko display M4032 (quite an old one, but I think the principle is still the same), then you have two possibilities:
1. The power to your LCD should be turned on according a certain sequence (especially time is important).
2. If you're not sure about the power-up sequence, you have to "reset" your LCD software wise.

For the 2nd possibility, it is then stated to wait at least 10 ms. I too had problems with this time. It seemed to bee too less. Therefore, I took a time of 50 ms. and that works allways.

It's also very important to very precisely follow the algorithm given in the datasheets, when you have to rely on the software reset after starting up the LC-display.