GA has a limit on the number of characters (actually bytes) for custom dimensions. It is set at 150 bytes which means if you attempt to pass a group of segments from Lytics to GA where the total is over 150 characters you will receive a warning (Parameter for Custom Dimension is too long (max 150)) in GA or Google Tag Manager and the segments will not be received in GA.

You can attempt to overcome this by reducing the name lengths of your segments or by deselecting API access while editing the segment in question. Disabling API access means the segments will not be 'public' and therefore will not be passed to GA. See fig.1 for details.

Fig. 1