Strange issue 06508: PL/SQL: could not find program unit could not be callled

we have been facing this strange issue quite frequently now..
following error is reported from forms..

06508: PL/SQL: could not find program unit being called@2RMSMFM_ORDER.ADDTOQ ORA-06512: at "RMS.EC_TABLE_OLO_AIUDR", line 78 ORA-04088: error during execution of trigger 'RMS.EC_TABLE_OLO_AIUDR'~ERROR -

If I check the package it is already valid..

OBJECT_NAME                         OBJECT_TYPE                 OWNER                                               STATUS

------------------------------ ------------------- ------------------------------ -------

RMSMFM_ORDER                                   PACKAGE                         RMS                                                      VALID

RMSMFM_ORDER                                   PACKAGE BODY            RMS                                                      VALID

RMSMFM_ORDER                                   SYNONYM                       PUBLIC                                                 VALID

RMSMFM_ORDER                                   SYNONYM                       ODIRMS                                              VALID

RMSMFM_ORDER                                   SYNONYM                       CUSTOM                                             VALID

Where as if I recompile the package the error goes away..this does not make any sense, what could be root cause of this issue?