Which drive do you use?
Did you get the settings (C2, caching) from a database or did you perform a detection within EAC?
If error correction blocks start lighting up, then there were errors on the disc or the reading failed.
The amount of the rows which are being displayed, is determined by the “error recovery” setting (F9 --> Extraction menu). In opposite to its description, this has nothing to do with the actual quality, but how long EAC will retry to read 16 sectors again and again before giving up.
Because audio-cds use neither an Error-Detection-Code (EDC) nor an Error-Correction-Code, the only error correction which is left, is CIRC (Cross Interleaved-Read-Solomon-Code), available on all CDs.
So if your drive cannot read the C2 info (or the setting is turned off), the only way to make (nearly) sure that a sectors has been read properly, is to read a sector many times and compare them.
If you read with C2 turned on, the sectors have to be read only once, so the extracting speed is faster (C2 capable drives can report bad sectors, without reading sectors twice).
To make a long story short, try to read in burst mode (without ANY error correction), which is sometimes better on “strange” discs. Read many times, and check if the CRC value changes.
If not, the copy should be OK.
Also check the resulting wave with an audio editor for noises.