CRS310 works when powered from CRS328-24P (and PoE voltage is auto-detected as 48V), but doesn't start when powered from (at least) Netgear GS110TP. Works when powered from the same Netgear switch through RBGPOE-CON-HP (which converts 48V 802.3af to 24V passive PoE), this switch also powers a few other 802.3af compliant devices just fine. So there may be an error in the product page https://mikrotik.com/product/crs310_1g_5s_4s_in - no 802.3af/at, only 18-57V passive PoE-in.
EDIT: CRS310 works when powered from a very old SMCGS8P-Smart switch (latest firmware from 2011, still available from Edge-Core) which also says to be 802.3af compliant (plus one high-power port, but no mention of 802.3at yet), perhaps PoE detection methods have changed since then.