You can send data through a serial link either TRUE or INVERTED. I am sure using HSEROUT the data is always true, whereas your serial LCD may be either true or inverted, if your serial LCD is set to accept data in inverted form, then you will see characters looking like gibberish.
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You say this works:SEROUT PORTB.1,6,[254,131,#HH,58]<br>
the 6 is telling me N9600 baud, which is inverted so you must reset in software the serial backpack to accept TRUE in order to read properly.