Cannot delete regs on a SQL table in Access - sql-server

Question

I have a SQL Server table linked in an Access app. If I try to delete records with a delete query there is no problem. But if I try to delete records directly in table or using a select query in datasheet mode Access doesn't allow me to delete the records and throws the following warning:
"The microsoft access database engine stopped the process because you and another user are attempting to change the same data at the same time."
The same happens when I try to update data. There is no other user modifying the data.
The problem is that we still have a lot of legacy forms that uses datasheet mode to alter o delete records instead of using queryes and, for now, changing all these forms is unthinkable.
¿Has anyone any idea of what could be happening?
Thanks!
FINAL EDIT:
The problem was a bit field that was set to nullable that, thanks to Kostas K. I discovered is not convertable to Access.
So, instead of this:
[FIELD] [bit] NULL
We need tis:
[FIELD] [bit] NOT NULL
ALTER TABLE [dbo].[TABLE] ADD DEFAULT ((0)) FOR [FIELD] GO
UPDATE: This locking only happens with new records added from Access, but not with the original records of the SQL table.
This is the script to create the table:
`
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [Chapas].[INFO_CHAPAS](
[ID_INFO_CHAPA] [int] IDENTITY(1,1) NOT NULL,
[COD_EQUIPO] [int] NULL,
[EQUIPO] [nvarchar](255) NULL,
[NUMERO_SERIE] [nvarchar](255) NULL,
[FASES] [nvarchar](255) NULL,
[VOLTAJE] [nvarchar](255) NULL,
[FRECUENCIA] [nvarchar](255) NULL,
[POTENCIA] [nvarchar](255) NULL,
[AÑO] [int] NULL,
[IMPRESO] [bit] NULL,
[SELECTOR_REGISTRO] [bit] NULL,
[USUARIO] [int] NULL,
[FECHA_IMPRESION] datetime NULL
CONSTRAINT [INFO_CHAPAS_PK] PRIMARY KEY NONCLUSTERED
(
[ID_INFO_CHAPA] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY
= OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [Chapas].[INFO_CHAPAS] ADD DEFAULT ((0)) FOR [IMPRESO]
GO
`